In children 18 years and under, what promotes recurrent shoulder instability after traumatic anterior shoulder dislocation? A systematic review and meta-analysis of risk factors.

BACKGROUND: Skeletal maturity and age-related changes in the composition of the glenoid labrum and joint capsule may influence rates of recurrent instability in children. We systematically review risk factors which predispose children to recurrent shoulder instability. METHODS: The systematic review-concerned studies published before May 2015. Statistical analysis was undertaken to compare rates of recurrence for each extracted risk factor. Pooled ORs were analysed using random effects meta-analysis. RESULTS: 6 retrospective cohort studies met the inclusion criteria. 8 risk factors were identified across the studies including age, sex, shoulder dominance and injury side, mechanism of injury, state of physis closure, and Hill-Sachs and Bankart lesions. The rate of recurrent instability was 73%. Children aged 14-18 years were 24 times more likely to experience recurrent instability than children aged 13 years and less (93% vs 40%; OR=24.14, 95% CI (3.71 to 156.99), Z=3.33, p=0.001, I(2)=6.83%). There was a non-significant trend indicating males were 3.4 times more likely to experience recurrent instability (OR=3.44, 95% CI (0.98 to 12.06), Z=1.93, p=0.053, I(2)=0%). Analysis of one study found that children with a closed physis are 14 times more likely to experience recurrent instability compared with those with an open physis (OR=14.0, 95% CI (1.46 to 134.25), Z=2.29, p=0.02, I(2)=0%) . CONCLUSIONS: Male children aged 14 years and over had the greatest risk of recurrent shoulder instability following a first-time traumatic anterior shoulder dislocation. This meta-analysis summarises a mix of 6 acceptable and poor quality level III retrospective cohort studies. Further examination of this population with blinded prospective cohort studies will assist clinicians in the appropriate management of first-time traumatic anterior shoulder dislocation.

Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis.

BACKGROUND: Recurrent instability following a first-time anterior traumatic shoulder dislocation may exceed 26%. We systematically reviewed risk factors which predispose this population to events of recurrence. METHODS: A systematic review of studies published before 1 July 2014. Risk factors which predispose recurrence following a first-time traumatic anterior shoulder dislocation were documented and rates of recurrence were compared. Pooled ORs were analysed using random-effects meta-analysis. RESULTS: Ten studies comprising 1324 participants met the criteria for inclusion. Recurrent instability following a first-time traumatic anterior shoulder dislocation was 39%. Increased risk of recurrent instability was reported in people aged 40 years and under (OR=13.46), in men (OR=3.18) and in people with hyperlaxity (OR=2.68). Decreased risk of recurrent instability was reported in people with a greater tuberosity fracture (OR=0.13). The rate of recurrent instability decreased as time from the initial dislocation increased. Other factors such as a bony Bankart lesion, nerve palsy and occupation influenced rates of recurrent instability. CONCLUSIONS: Sex, age at initial dislocation, time from initial dislocation, hyperlaxity and greater tuberosity fractures were key risk factors in at least two good quality cohort studies resulting in strong evidence as concluded in the GRADE criteria. Although bony Bankart lesions, Hill Sachs lesions, occupation, physiotherapy treatment and nerve palsy were risk factors for recurrent instability, the evidence was weak using the GRADE criteria-these findings relied on poorer quality studies or were inconsistent among studies.

The immediate and subsequent impact of a first-time traumatic anterior shoulder dislocation in people aged 16-40: Results from a national cohort study.

BACKGROUND: Limited evidence exists which details changes in quality of life, shoulder activity level, kinesiophobia, shoulder pain and disability following a first-time traumatic anterior shoulder dislocation (FTASD) in people treated non-operatively. This study had three objectives: (1) to examine quality of life, pain, disability and kinesiophobia after an FTASD within 12 weeks, (2) to examine whether these variables were different in people with and without recurrent shoulder instability and (3) to assess how these variables changed over 12 months. METHODS: A prospective cohort study was undertaken in people with an FTASD aged between 16 and 40 years. Measures of quality of life, kinesiophobia, shoulder activity, shoulder pain and disability were recorded within 12 weeks of an FTASD and at 3, 6, 9 and 12 months. RESULTS: An FTASD negatively impacted quality of life, shoulder pain and function and these variables improved over time. People with recurrent shoulder instability had poorer quality of life 12 months after an FTASD. Across the entire cohort, kinesiophobia did not significantly change across time in people following an FTASD. CONCLUSIONS: Quality of life was significantly affected by an FTASD in people with recurrent shoulder instability. Across the entire cohort of people with an FTASD, kinesiophobia remained elevated in people following an FTASD. LEVEL OF EVIDENCE: Level 1 prognostic study.

Exploring strategies used following a group-based fatigue management programme for people with multiple sclerosis (FACETS) via the Fatigue Management Strategies Questionnaire (FMSQ).

OBJECTIVES: To explore cross-sectional patterns of use of fatigue management strategies in people with multiple sclerosis (MS) who had attended a group-based fatigue management programme, Fatigue: Applying Cognitive behavioural and Energy effectiveness Techniques to lifeStyle ('FACETS'). In a multicentre randomised controlled trial (RCT) the FACETS programme was shown to reduce fatigue severity and improve self-efficacy and quality of life. DESIGN: A questionnaire substudy within a RCT involving the self-completed Fatigue Management Strategies Questionnaire (FMSQ). The FMSQ includes: (1) closed questions about the use and helpfulness of fatigue management strategies taught in FACETS and (2) open items about changes to lifestyle, attitudes or expectations, barriers or difficulties encountered and helpful strategies not covered in FACETS. PARTICIPANTS: All had a clinical diagnosis of MS, significant fatigue, were ambulatory and had attended at least 4 of 6 scheduled FACETS sessions. METHODS: Participants (n=72) were posted the FMSQ with a prepaid return envelope 4 months after the end of the FACETS programme. RESULTS: 82% (59/72) of participants returned the FMSQ. The fatigue management strategies most frequently used since attending FACETS were prioritisation (80%), pacing (78%), saying no to others (78%), grading tasks (75%) and challenging unhelpful thoughts (71%). Adding in those participants who were already using the respective strategies prior to FACETS, the three most used strategies at 4 months were prioritisation (55/59), grading (54/59) and pacing (53/58). Free-text comments illustrated the complex interplay between attitudes/expectations, behaviours, emotions and the environment. Issues related to expectations featured strongly in participants' comments. Expectations (from self and others) were both facilitators and barriers to effective fatigue management. CONCLUSIONS: Individuals' comments highlighted the complex, multifaceted nature of fatigue management. Revising expectations and a greater acceptance of fatigue were important shifts following the programme. Findings support the relevance of a cognitive behavioural approach for fatigue management. Booster sessions might be a useful addition to the FACETS programme. TRIAL REGISTRATION NUMBER: Current controlled trials ISRCTN76517470; Results.

The in vitro influence of different culture conditions on the potential of sheep rib perichondrium to form hyaline-like cartilage. Evaluation of gluing materials used for in vivo graft fixation.

The effectiveness of autologous rib perichondrium for repair of full-thickness hyaline cartilage defects has been shown experimentally and clinically in various reports. The purpose of this study was to examine the behaviour of sheep rib perichondrial tissue under in vitro conditions and the influence of different culture matrices in order to evaluate possible stimulating effects. Rib perichondrium was obtained from sheep used for an experimental in vivo trial. After removal of adjacent cartilage remnants the tissue was divided and specimens cultured for 14 days in different ways. Explants cultured on collagen sponges (group A), fibrin glue (group B) and cellulose acetate filter (group C) were examined histologically, histochemically, histomorphometrically and autoradiographically. Clear differentiation of perichondrial cells towards a chondrocyte-like cell shape, particularly in the proliferation zone, was noticed on all matrices. These cells synthesized new matrix substances comparable to the ground substance normally present in hyaline cartilage. Morphometric comparison of tissue differentiation on different culture matrices revealed no significant differences in proliferation rates.

The unmet needs of young people who have had a stroke: results of a national UK survey.

BACKGROUND: Most stroke-related studies have consisted of people over the age of 65. This study examined the unmet needs of young people with stroke, living in community housing in the UK. METHOD: People with a stroke (>1 year ago), in two age bands (18-45; 46-65) were sent the Southampton Needs Assessment Questionnaire for people with Stroke. RESULTS: 315 out of 639 (49%) questionnaires were returned (mean age 55, SD 9; 189 males, 126 females). The median number of unmet needs reported was two (IQR 0-6). The most frequently reported unmet needs were: provision of information about the responders' stroke (45%); assistance with finances (24%); non-care activities (19%); and intellectual fulfillment (17%). Responders in the younger age group reported significantly more unmet needs than responders in the older age group (for a holiday, intellectual fulfillment and family support). Responders with poor mobility reported significantly more unmet needs than responders with average and good mobility for 15 unmet needs (three most pressing: respite care/short breaks; adaptations; and access to community environment). Responders who did not return to work reported significantly more unmet needs than responders who had reduced hours or changed jobs and people who returned to the same job with the same hours for seven unmet needs (three most pressing: help with finances; a holiday and speech therapy). CONCLUSION: People of younger age, with poorer mobility and those unable to return to work, report most unmet needs. Further work needs to be done within the community, with employers and professionals, in relation to education and the provision of specifically targeted information in order to facilitate participation and autonomy for people with stroke.

To what extent are the needs of severely disabled people met by community rehabilitation services? A follow-up study.

PURPOSE: To evaluate which needs of disabled people would be met over a one year follow-up period and to examine which factors would be predictive of identifying those people who had more needs met from those who had fewer needs met. METHOD: A follow-up study of a cohort of community dwelling disabled people (aged 16-65) from two NHS Health Districts in Southern England with contrasting patterns of rehabilitation provision, who had participated in a cross-sectional interview study one year previously which had assessed their met and unmet needs. The Southampton Needs Assessment Questionnaire was used to examine needs. Disability was evaluated with the OPCS Disability and Severity Scales and perceived health status with the SF-36. RESULTS: Participation rate at follow-up was 92 %. Of the 300 baseline unmet needs reported by 69 of the 77 participants 33% had been met at follow-up. People whose disability had increased more and/or whose mental health status had improved more had greater percentages of their baseline needs met. There was a non-significant trend for smaller percentages of baseline needs to be met in Basingstoke than in Southampton. CONCLUSIONS: At ground level, disabled people's views were taken into account, to some extent, in the provision of rehabilitation services. This input should be made at a higher level, in the overall shaping of services.

Met and unmet needs reported by severely disabled people in southern England.

PURPOSE: To examine the met and unmet needs for rehabilitation of disabled people living in the community in Southern England. METHOD: A cross sectional interview study of people with a primary physical disability, aged 1665. Disabled people were randomly selected from two existing disability registers, which comprised disabled people who had been identified by community rehabilitation services as being in need of regular surveillance by formal assessment of their care needs. A new semi-structured needs assessment questionnaire was developed and validated for the study (the Southampton Needs Assessment Questionnaire, SNAQ). Level of disability was examined with the OPCS Disability and Severity Scales. RESULTS: Ninety three disabled people participated. Their median (IQR) OPCS score was 8 (6-10). Participants reported a median (IQR) of three unmet needs (2-7). The most prevalent unmet needs were for adaptations, equipment, physiotherapy and wheelchairs, rather than unmet needs for intellectual and social fulfilment. CONCLUSIONS: Disabled people who were already in touch with community rehabilitation services continued to express unmet needs for further services. Meeting the more basic needs relating to people's housing, equipment, physiotherapy and wheelchairs may enable them to be more independent and fulfilled in other areas of their lives.

A study to evaluate the met and unmet needs of members belonging to Young Stroke groups affiliated with the Stroke Association.

PURPOSE: To examine the met and unmet needs of young people with stroke who accessed services run by the Stroke Association. METHODS: One hundred and thirty-five out of 200 members of 14 participating Young Stroke groups completed and returned the postal version of the Southampton Needs Assessment Questionnaire for Stroke questionnaire. RESULTS: Young Stroke group members had a median of five unmet needs. An analysis of these needs showed that information about the person's stroke, help with finances, assistance with non-care activities (e.g. help with social activities) and help with maintaining intellectual fulfilment were the four most frequently reported ones. There was no association between the number of unmet needs reported and factors such as age, time since stroke and social class. CONCLUSIONS: Young Stroke group members may be more aware of what their unmet needs are and have better knowledge in accessing existing health and social service resources. Nevertheless, these findings show that people with stroke considered the provision of information geared to their own needs as important. Statutory services should personalize information to individual's specific situation and should also tackle other problems, not only physical ones, experienced by young people with strokes.

Needs of carers of severely disabled people: are they identified and met adequately?

OBJECTIVE: To examine the unmet needs of informal carers of community dwelling disabled people and to compare their perspectives to those of disabled people and nominated professionals. It was hypothesised that a poor recognition of carers' needs could have implications for carers' well- being and thus their ability to maintain their caring role. Need was defined as a service or a resource that would confer a health or rehabilitation gain. DESIGN: Face to face interviews with carers and disabled participants, telephone interviews with professionals (Southern England). Disabled participants had been selected randomly from two disability registers. MAIN OUTCOME MEASURES: The Southampton Needs Assessment Questionnaire (carers version), SF-36 (carers' health status). RESULTS: Carers experienced similar health status to people in the general population. The most frequently carer-reported unmet needs were for short breaks, domestic help and respite care. Carers who had reported unmet need for short breaks had significantly poorer levels of mental health and vitality (SF-36) than carers who had not reported this. Similar numbers of unmet carers' needs were reported by disabled participants, professionals and carers themselves. In terms of type of unmet needs, poor concordance between carers and disabled participants occurred in 52% of cases: carers reported more unmet needs than disabled participants for short breaks and domestic help. Poor concordance scores between carers and professionals occurred in 59% of cases: carers reported more unmet needs for short breaks than professionals and professionals reported more unmet needs for formal respite care. CONCLUSION: In line with recent legislation, carers' needs must be independently addressed and services, especially for flexible community support such as short break services, must be developed specifically to meet the needs of carers. Further research is warranted to evaluate whether recent legislation for carers has any effect on carers' well-being and ability to cope with their caring role.

Establishment of genetic linkage by allele-specific polymerase chain reaction: application to the lignin peroxidase gene family of Phanerochaete chrysosporium.

Determining linkage is problematic for genes lacking easily identifiable phenotypes and for organisms without well-defined genetic recombination systems. Phanerochaete chrysosporium with its lignin peroxidase (LiP) gene family typifies these difficulties. We describe an experimental approach whereby the segregation of specific alleles is directly monitored during sexual fruiting. The method establishes linkage relationships among genes for which there are no mutations, and it is applicable to a wide range of genes, gene families and organisms. Using this approach, five P. chrysosporium linkage groups were identified. Ten LiP genes were distributed among three of these groups. One co-segregating group contained eight closely linked LiP genes. Another LiP gene was linked to a cellobiohydrolase gene cluster. These genetic linkages were consistent with physical mapping by pulsed field gel electrophoresis. Based on the identification of allelic relationships, a uniform nomenclature for LiP genes is also described.

Rapid analysis of abietanes in conifers.

Diterpene resin acids are major constituents of conifer oleoresin and play important roles in tree defense against insects and microbial pathogens. The tricyclic C-20 carboxylic acids are generally classified into two groups, the abietanes and the pimaranes. The abietanes have conjugated double bonds and exhibit characteristic UV spectra. Here, we report the analysis of abietanes by reversed-phase high-performance liquid chromatography using multiwavelength detection to optimize quantification of underivatized abietic, neoabietic, palustric, levopimaric, and dehydroabietic acids. The utility of the method is demonstrated with methanol extracts of white spruce (Picea glauca) phloem, and representative concentrations are reported.

Measuring autonomy in disabled people: Validation of a new scale in a UK population.

OBJECTIVE: To evaluate the validity and reliability of an English version of the Impact on Participation and Autonomy Questionnaire (IPA). The original Dutch IPA has been shown to load onto five factors. DESIGN: A validation study. SETTING: Outpatients clinics and people's homes. SUBJECTS: Two hundred and thirteen people with multiple sclerosis, rheumatoid arthritis, spinal cord injury, and general practice attendees, stratified by level of disability (median age 54, 42% male, 58% female). INCLUSION CRITERIA: English as first language, aged 18-75, Mental Status Questionnaire score >6. INTERVENTIONS: Self- and interviewer-administered outcome measures. MAIN MEASURES: IPA, including one new item (66 participants completed the IPA on a second occasion). OTHER MEASURES: Short Form-36 Health Survey (SF-36), London Handicap Scale, three domains of the Functional Limitations Profile (FLP): household management, social integration, emotion. RESULTS: Confirmatory factor analysis confirmed the construct validity of the IPA (Normal Fit Index = 0.98, Comparative Fit Index = 0.99), indicating a good fit to the model. Convergent and discriminant validity were confirmed by the predicted associations, or lack of, with the exception of a poor association between the 'social life/relationships' IPA subscale and FLP-emotion. Internal reliability of the IPA was confirmed (Cronbach alphas >0.8; item-total correlations for all subscales >0.5). Test-retest reliability was confirmed for all items (weighted kappas >0.6) and subscales (intraclass correlation coefficients >0.90). CONCLUSIONS: The English IPA is a valid, reliable and acceptable measure of participation and autonomy in people with a range of conditions and can make a unique and fundamental contribution to outcome assessment. Further research is required to examine the responsiveness of the IPA to change over time, its clinical utility and suitability for use with people from ethnic minorities and with older people.

Glyoxal oxidase of Phanerochaete chrysosporium: its characterization and activation by lignin peroxidase.

Glyoxal oxidase (GLOX) is an extracellular H2O2-generating enzyme produced by ligninolytic cultures of Phanerochaete chrysosporium. The production, purification, and partial characterization of GLOX from agitated cultures are described here. High-oxygen levels are critical for GLOX production as for lignin peroxidase. GLOX purified by anion-exchange chromatography appears homogeneous by NaDod-SO4/PAGE (molecular mass = 68 kDa). However, analysis by isoelectric focusing indicates two major bands (pI 4.7 and 4.9) that stain as glycoproteins as well as for H2O2-producing activity in the presence of methylglyoxal. Purified GLOX shows a marked stimulation in activity when incubated with Cu2+; full activation takes more than 1 hr with 1 mM CuSO4 at pH 6. The steady-state kinetic parameters for the GLOX oxidation of methylglyoxal, glyceraldehyde, dihydroxyacetone, glycolaldehyde, acetaldehyde, glyoxal, glyoxylic acid, and formaldehyde, were determined by using a lignin peroxidase coupled-assay at pH 4.5. Of these substrates, the best is the extracellular metabolite methylglyoxal with a Km of 0.64 mM an apparent rate of catalysis, kcat, of 198 s1 under air-saturated conditions. The Km for oxygen is greater than the concentration of oxygen possible at ambient pressure--i.e., >1.3 mM at 25 degrees C. Importantly, oxygen-uptake experiments show that purified GLOX is inactive unless coupled to the peroxidase reaction. With this coupled reaction, for each mol of methylglyoxal, veratryl alcohol (a lignin peroxidase substrate), and oxygen consumed, 1 mol each of pyruvate and veratraldehyde is produced. The importance of these results is discussed in relation to the physiology of lignin biodegradation and possible extracellular regulatory mechanisms for the control of oxidase and peroxidase activities.

Cloning and characterization of cDNA encoding glyoxal oxidase, a H2O2-producing enzyme from the lignin-degrading basidiomycete Phanerochaete chrysosporium.

Glyoxal oxidase is produced by ligninolytic cultures of the white-rot fungus Phanerochaete chrysosporium and is a source of the extracellular H2O2 that is required by ligninolytic peroxidases. We report here the cloning and characterization of glx-1c cDNA, which encodes glyoxal oxidase. The deduced mature protein has 537 amino acids, a molecular size of 57 kDa, and a pI of 5.1. Five potential N-glycosylation sites are present. The predicted N-terminal sequence is identical to the experimentally determined sequence of purified enzyme and is preceded by a leader peptide of 22 amino acids. The sequence of glx-1c lacks significant homology with known sequences. Specific comparisons were made between the glx-1c translated sequence and that of galactose oxidase from Dactylium dendroides because of previously observed catalytic similarities of the enzyme. Although no significant homology is observed, in both cases extensive beta-sheet regions are predicted from the primary sequences. Glyoxal oxidase activity correlates with transcript levels and is also coordinate with the lignin peroxidases in nutrient nitrogen-starved cultures.

Involvement of a new enzyme, glyoxal oxidase, in extracellular H2O2 production by Phanerochaete chrysosporium.

The importance of extracellular H2O2 in lignin degradation has become increasingly apparent with the recent discovery of H2O2-requiring ligninases produced by white-rot fungi. Here we describe a new H2O2-producing activity of Phanerochaete chrysosporium that involves extracellular oxidases able to use simple aldehyde, alpha-hydroxycarbonyl, or alpha-dicarbonyl compounds as substrates. The activity is expressed during secondary metabolism, when the ligninases are also expressed. Analytical isoelectric focusing of the extracellular proteins, followed by activity staining, indicated that minor proteins with broad substrate specificities are responsible for the oxidase activity. Two of the oxidase substrates, glyoxal and methylglyoxal, were also identified, as their quinoxaline derivatives, in the culture fluid as secondary metabolites. The significance of these findings is discussed with respect to lignin degradation and other proposed systems for H2O2 production in P. chrysosporium.

Enzymatic release of halogens or methanol from some substituted protocatechuic acids.

Four strains of gram-negative bacteria capable of growing at the expense of 5-chlorovanillate were isolated from soil, and the metabolism of one strain was studied in particular detail. In the presence of alpha, alpha'-bipyridyl, a suspension of 5-chlorovanillate-grown cells accumulated 5-chloroprotocatechuate from 5-chlorovanillate; in the absence of inhibitor these compounds, and various other 5-substituted protocatechuates and vanillates, were oxidized to completion. Cell suspensions of this strain grown on 5-chlorovanillate or vanillate released chloride quantitatively from 5-chlorovanillate and released methanol from syringate. Extracts of cells grown with 4-hydroxybenzoate, vanillate, or syringate possessed high levels of both protocatechuate 4,5-dioxygenase and 2-pyrone-4,6-dicarboxylate hydrolase; extracts from acetate-grown cells did not. Protocatechuate 4,5-dioxygenase, purified from strains that could grow with 5-chlorovanillate, oxidized 5-halogeno-protocatechuates and 3-O-methylgallate with the formation of 2-pyrone-4,6-dicarboxylate. A crude extract converted 5-chloroprotocatechuate into pyruvate plus oxaloacetate. On the basis of these observations, a meta-fission reaction sequence is proposed for the bacterial degradation of vanillate and protocatechuate substituted at C-5 of the benzene ring with halogen or methoxyl.

Cartilage-flow phenomenon and evidence for it in perichondrial grafting.

The cartilage-flow phenomenon has been frequently described but not in connection with transplantation procedures for treatment of cartilage lesions. Consequently, we examined this particular phenomenon in an experimental sheep model originally set up to study the use of perichondrial grafts for repair of full-thickness cartilage lesions. Osteochondral lesions were made in nonweight-bearing and weight-bearing areas of knee joints in 36 sheep. The defects were filled with autologous rib perichondrial grafts and secured by either collagen sponges or fibrin glue (n = 24 animals). Defects without perichondrial grafts served as controls (n = 12 animals). Following 1 week of immobilisation of the operated leg, the plaster was removed, and animals were allowed to move freely. Animals were killed after 2, 4, 12 and 16 weeks. Grafts including rims of original surrounding cartilage and bone were removed and investigated by means of macroscopy, histology and micromorphology, including scanning electron microscopy and analysis under polarized light. Cartilage flow was observed in all specimens by 4 weeks after drilling the defects, independent of the weight-bearing condition. These flow formations exhibited a bending of the collagen fibres centrally into the defects, reduction of metachromasia, cell cluster formation and areas of reduced cell density. Time-dependent flow formations were observed related to the weight-bearing condition and whether or not the defects had been grafted. In grafted, non-weight-bearing defects further cartilage flow was stopped 8 weeks after transplantation by the growing perichondrial transplants, which had filled the defects completely. In contrast, control defects exhibited further flow formations in both areas. The same was observed in grafted defects in the weight-bearing area. In defects without complete filling as not enough spontaneously growing fibrous tissue had arisen from the bottom of the defects, two different observations were made: either the defects exhibited a fungiform mass of fibrous tissue that had overgrown the lateral flow formations, or the central mass of fibrous tissue was overgrown by the lateral flow formations. In conclusion, cartilage flow seems to be a mechanically induced phenomenon at the rims of cartilage lesions that contributes little to the reduction of size of large osteochondral defects. There was no evidence for new cartilage proliferation or production of cartilaginous matrix at the rims of the lesions.

Kinetics of Mn3+-oxalate formation and decay in reactions catalyzed by manganese peroxidase of Ceriporiopsis subvermispora.

The kinetics of Mn3+-oxalate formation and decay were investigated in reactions catalyzed by manganese peroxidase (MnP) from the basiomycete Ceriporiopsis subvermispora in the absence of externally added hydrogen peroxide. A characteristic lag observed in the formation of this complex was shortened by glyoxylate or catalytic amounts of Mn3+ or hydrogen peroxide. MnP titers had a minor effect on this lag and did not influence the decay rate of the complex. In contrast, Mn2+ and oxalate drastically affected maximal concentrations of the Mn3+-oxalate complex formed, the decay of which was accelerated at high Mn2+ levels. The highest concentration of complex was obtained at pH 4.0, whereas an inverse relationship was found between the pH of the reaction and the decay rate of the complex with MnP present. In the absence of MnP, the best fit for the decay kinetics of the complex gave an order of 3/2 at concentrations in the range of 30-100 microM, with a kobs = 0.012 min-1 M-0.5 at pH 4.0. The rate constant increases at lower pH values and decreases at high oxalate concentrations. The physiological relevance of these findings is discussed.