Associations between 24-h movement behaviors and self-rated health: a representative sample of school-aged children and adolescents in Okinawa, Japan.

OBJECTIVES: This study aimed to determine the associations between adherence to 24-h movement behavior guidelines and self-rated health (SRH) among Japanese adolescents according to their age group. STUDY DESIGN: This was a cross-sectional study. METHODS: Probability proportional sampling data, which were collected from six regions of Okinawa Prefecture, Japan, considering the number of schools, included 2408 fifth-grade students (aged 10-11 years) in 31 elementary schools and 4360 eighth-grade students (aged 13-14 years) in 30 junior high schools. SRH, moderate-to-vigorous physical activity (MVPA), screen time (ST), sleep duration, and confounding factors (sex, weight status, family affluence, parental support, school satisfaction, and school demands) were self-reported. RESULTS: The logistic regression models showed that adherence to ST and sleep recommendations in elementary school students was associated with a high prevalence of good health only, whereas adherence to only MVPA, only sleep, ST and sleep, MVPA and sleep, and all three recommendations were associated with a high prevalence of good health among junior high school students. All combinations that included achievement of the recommended sleep duration were associated with SRH. CONCLUSIONS: Achieving 24-h movement behavior guidelines, particularly sleep recommendations, is associated with better perceived health in school-aged children, especially in adolescents.

Nerve growth factor regulation and production by macrophages in osteoarthritic synovium.

Nerve growth factor (NGF) functions to modulate osteoarthritis (OA)-associated pain. Although recent studies suggest that tumour necrosis factor (TNF)-α and interleukin (IL)-1ß mediate NGF activity in human synovial fibroblasts, the regulation of NGF expression in human synovial macrophages remains unclear. Here, we examined the role of macrophages in the production and regulation of synovial (SYN) NGF in osteoarthritic knee joints by examining the mRNA expression of TNF-α and IL-1ß in freshly isolated CD14-positive (macrophage-rich fraction) and CD14-negative cells (fibroblast-rich fraction) in synovial tissue from OA patients by quantitative polymerase chain reaction. We also examined the effects of IL-1ß and TNF-α on NGF mRNA expression in cultured CD14-positive (macrophage-rich fraction) and CD14-negative cells (fibroblast-rich fraction). In addition, to examine the contribution of macrophages to NGF, TNF-α and IL-1ß expression, we injected clodronate liposomes systemically into STR/Ort mice, an osteoarthritis animal model, to deplete macrophages. TNF-α and IL-1ß mRNA levels in CD14-positive cells from the SYN of OA patients was significantly higher than that in CD14-negative cells, while NGF expression did not differ markedly between the two cell fractions. In addition, treatment of human cultured CD14-positive and -negative cells with IL-1ß and TNF-α enhanced NGF mRNA and protein levels. Expression of NGF, IL-1ß and TNF-α was also reduced significantly in STR/Ort mice upon macrophage depletion. These findings suggest that IL-1ß and TNF-α regulate NGF expression and production in synovial macrophages and fibroblasts in osteoarthritic joints.

Synovial macrophage-derived IL-1ß regulates the calcitonin receptor in osteoarthritic mice.

Recent studies have reported that calcitonin gene-related peptide (CGRP) contributes to joint pain. However, regulation of the CGRP/CGRP receptor signalling in osteoarthritis (OA) is not fully understood. To investigate the regulation of CGRP/CGRP receptor signalling by macrophages in the synovial tissue (ST) of OA joints, we characterized the gene expression profiles of CGRP and CGRP receptors in the ST of OA mice (STR/Ort). In addition, we examined whether macrophage depletion by the systemic injection of clodronate-laden liposomes affected the expression of CGRP and CGRP receptors in ST. CD11c(+) macrophages in the ST of STR/Ort and C57BL/6J mice were analysed by flow cytometry. Real-time polymerase chain reaction (PCR) was used to evaluate the expression of interleukin (IL)-1ß, CGRP, calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1) in F4/80(+) and F4/80(-) cells. The effects of IL-1ß on the expression of CGRP and CLR by cultured synovial cells were also examined. The percentage of CD11c(+) macrophages in the ST of STR/Ort was higher than that in C57/BL6J mice. Notably, the F4/80(+) cell fraction expressed IL-1ß highly, whereas the F4/80(-) cell fraction expressed CGRP, CLR, and RAMP1 highly. In addition, expression of the IL-1ß and CLR genes was increased in ST, but was decreased upon macrophage depletion, and the IL-1ß treatment of cultured synovial cells up-regulated CLR. Taken together, the present findings suggest that synovial macrophages are the major producers of IL-1ß and regulators of CLR in OA mice. Therefore, macrophages and IL-1ß may be suitable therapeutic targets for treating OA pain.

CD11c(+) macrophages and levels of TNF-α and MMP-3 are increased in synovial and adipose tissues of osteoarthritic mice with hyperlipidaemia.

To understand more clearly the link between osteoarthritis and hyperlipidaemia, we investigated the inflammatory macrophage subsets and macrophage-regulated matrix metalloprotease-3 (MMP-3) and A disintegrin and metalloprotease with thrombospondin motifs-4 (ADAMTS4) in synovial (ST) and adipose tissues (AT) of osteoarthritic mice with hyperlipidaemia (STR/Ort). CD11c(+) F4/80(+) CD11b(+) macrophage populations in the ST and AT of 9-month-old STR/Ort and C57BL/6J mice were characterized and compared by flow cytometry and real-time polymerase chain reaction (PCR) analyses. Expression of tumour necrosis factor (TNF)-α, MMP-3 and ADAMTS4, and the response of these factors to anionic liposomal clodronate induced-macrophage depletion were also evaluated by real-time PCR. Expression of TNF-α in CD11c(+) cells, which were isolated by magnetic beads, was compared to CD11c(-) cells. In addition, the effect of TNF-α on cultured synovial fibroblasts and adipocytes was investigated. CD11c(+) F4/80(+) CD11b(+) macrophages were increased in ST and AT of STR/Ort mice. The CD11c(+) cell fraction highly expressed TNF-α. Expression of TNF-α and MMP3 was increased in ST and AT, and was decreased upon macrophage depletion. TNF-α treatment of cultured synovial fibroblasts and adipocytes markedly up-regulated MMP-3. CD11c(+) F4/80(+) CD11b(+) macrophages were identified as a common inflammatory subset in the AT and ST of STR/Ort mice with hyperlipidaemia. The induction of inflammation in AT and ST may be part of a common mechanism that regulates MMP3 expression through TNF-α. Our findings suggest that increased numbers of CD11c(+) macrophages and elevated levels of TNF-α and MMP-3 in AT and ST may explain the relationship between hyperlipidaemia and OA.

[Decrease in allogenic transfusions due to the spread of use of postoperative retransfusion systems in knee replacement surgery]. / Disminución de las transfusiones alogénicas por la generalización del uso de recuperadores de sangre postoperatorios en cirugía de prótesis de rodilla.

OBJECTIVES: Surgical teams have several tools in order to reduce the need for postoperative allogenic transfusion. Postoperative autotransfusion of unwashed shed blood has become common practice for total knee replacement surgery since 2006 in our hospital. This study was designed to evaluate if this practice has reduced allogenic blood transfusions. MATERIAL AND METHODS: A retrospective study comparing two cohorts, group 2004 with patients operated on for total knee replacement during the year 2004, before the use of the retransfusion system, and group 2008, patients operated on in the year 2008, with regular use of the retransfusion system. Gender, preoperative and postoperative haemoglobin levels, total amount of calculated erythrocytes lost, reinfusion of shed blood and allogenic blood transfusion during hospital stay were recorded. RESULTS: Both groups were similar as regards gender, preoperative and postoperative hemoglobin levels, and total amount of erythrocytes lost. The proportion of transfused patients was significantly lower in group 2008 versus group 2004 (20.18% versus 42.19%), with a relative risk of being transfused of 0.47 and a NNT of 4.54. P=.0017. CONCLUSIONS: In our hospital the use of postoperative retransfusion systems has reduced the proportion of transfused patients during hospitalization for total knee replacement surgery, although this result cannot be generalized due to the lack of a fixed transfusion trigger.

Antibodies against 70-kD heat shock cognate protein inhibit mediated nuclear import of karyophilic proteins.

Previously, we found that anti-DDDED antibodies strongly inhibited in vivo nuclear transport of nuclear proteins and that these antibodies recognized a protein of 69 kD (p69) from rat liver nuclear envelopes that showed specific binding activities to the nuclear location sequences (NLSs) of nucleoplasmin and SV-40 large T-antigen. Here we identified this protein as the 70-kD heat shock cognate protein (hsc70) based on its mass, isoelectric point, cellular localization, and partial amino acid sequences. Competition studies indicated that the recombinant hsc70 expressed in Escherichia coli binds to transport competent SV-40 T-antigen NLS more strongly than to the point mutated transport incompetent mutant NLS. To investigate the possible involvement of hsc70 in nuclear transport, we examined the effect of anti-hsc70 rabbit antibodies on the nuclear accumulation of karyophilic proteins. When injected into the cytoplasm of tissue culture cells, anti-hsc70 strongly inhibited the nuclear import of nucleoplasmin, SV-40 T-antigen NLS bearing BSA and histone H1. In contrast, anti-hsc70 IgG did not prevent the diffusion of lysozyme or 17.4-kD FITC-dextran into the nuclei. After injection of these antibodies, cells continued RNA synthesis and were viable. These results indicate that hsc70 interacts with NLS-containing proteins in the cytoplasm before their nuclear import.

Safety of ofloxacin (OFLX) and fosfomycin sodium (FOM) ear drops.

OBJECTIVE: The objective of this study is to evaluate the safety of two ear drops, Ofloxacin (OFLX: Taribid Otic Solution, Daiichi Seiyaku) and Fosfomycin sodium (FOM: Fosmicin S, Meiji Seiyaku). METHODS: Albino guinea pigs were used as experimental animals, and the ototoxicity was evaluated by means of threshold changes in the compound action potentials (CAP), when topically applied to the middle ear cavity of the guinea pig. The sound stimuli applied were; click sound, with tone bursts of 8 kHz, 4 kHz, and 2 kHz. In one group of animals, after one application of the ear drops in the right middle ear cavity, the change in CAP was compared with a contralateral saline control at 24h, one week, and four weeks. In other group of animals, the ear drops were applied into the middle ear cavity for seven consecutive days and the CAP was measured at 24h. RESULTS: At 24h the CAP threshold for click, 8 and 4 kHz elevated significantly for both the saline and ear drop treatment, but the threshold returned to normal when measured at 7 days and 28 days. Seven consecutive days of ear drops administration resulted in no reduction in the CAP for either ear drops. CONCLUSIONS: Based on the lack of changes in the CAP, these two ear drops studied did not show any significant ototoxicities.

Monitoring Protein Synthesis in Caenorhabditis elegans Using SILAC.

The static levels of proteins are the net results of their production and clearance regulated by the activities of proteins involved in their synthesis, degradation, and transportation. Therefore, the information on the rates of protein synthesis and clearance is needed to understand the underlying dynamic nature of a proteome. In this chapter, the experimental technique, we use in our laboratory for monitoring the synthesis of individual proteins in Caenorhabditis elegans (C. elegans) is described. The technique utilizes a preisotopically labeled amino acid (13C6-Lys) as a precursor for protein synthesis and monitors the kinetics of the precursor incorporation into the newly synthesized proteins. C. elegans is a powerful animal model in various fields of biomedical science such as aging, developmental biology, and neurobiology. The experimental technique would, therefore, be useful for research laboratories using C. elegans as an animal model.

Site-Specific Quantification of Lysine Acetylation Using Isotopic Labeling.

Acetylation of ɛ-amino group of lysine is one of the most common protein posttranslational modifications. The modification is reversible and catalyzed by lysine acetyltransferases in one direction and lysine deacetylases in the other direction. Although numerous lysine acetylation sites have been identified in many proteins involved in a diverse range of cellular processes, little has been revealed about the roles of this modification at the level of individual sites. To understand better the site-specific roles of this modification, it is important to investigate what fraction of each modified site is actually acetylated (stoichiometry of acetylation) in vivo in different physiological conditions. Here we describe a method that allows us to determine the site-specific stoichiometry of lysine acetylation. The method chemically acetylates all of the lysine residues in proteins that are not endogenously acetylated with an isotopically labeled acetyl (13C2-acetyl) group. The chemical treatment enables to determine the stoichiometry of acetylation at individual sites by measuring the abundance of the endogenously acetylated group (carrying a natulally abundant 12C2-acetyl group) and the chemically introduced acetyl group (carrying an isotopically labeled 13C2-acetyl group) in the subsequent mass spectrometry analysis. The method is most suitable to apply to pure proteins or relatively simple protein mixtures.

Fluid shear stress induces lipocalin-type prostaglandin D(2) synthase expression in vascular endothelial cells.

Ligands for peroxisome proliferator-activated receptor gamma, such as the thiazolidinedione class of antidiabetic drugs and 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), modulate various processes in atherogenesis. In search of cells that generate prostaglandin D(2) (PGD(2)), the metabolic precursor of 15d-PGJ(2), we identified PGD(2) from culture medium of endothelial cells. To study how PGD(2) production is regulated in endothelial cells, we investigated the role of fluid shear stress in the metabolism of PGD(2). Endothelial cells expressed the mRNA for the lipocalin-type PGD(2) synthase (L-PGDS) both in vitro and in vivo. Loading laminar shear stress using a parallel-plate flow chamber markedly enhanced the gene expression of L-PGDS, with the maximal effect being obtained at 15 to 30 dyne/cm(2). The expression began to increase within 6 hours after loading shear stress and reached the maximal level at 18 to 24 hours. In contrast, shear stress did not alter the expression levels of PGI(2) synthase and thromboxane A(2) synthase. In parallel with the increase in the expression level of L-PGDS, endothelial cells released PGD(2) and 15d-PGJ(2) into culture medium. These results demonstrate that shear stress promotes PGD(2) production by stimulating L-PGDS expression and suggest the possibility that a peroxisome proliferator-activated receptor gamma ligand is produced in vascular wall in response to blood flow.

Correlation of loss of alleles on the short arms of chromosomes 11 and 17 with metastasis of primary breast cancer to lymph nodes.

To examine the role of loss of heterozygosity (LOH) during tumor development and/or progression, we looked for correlations between metastasis of breast cancer to a regional lymph node(s) and LOH of chromosomal arms 11p, 13q, 16q, 17p, and 17q, where frequent losses in primary tumors have been detected. No correlation between lymph node metastasis and LOH of chromosomes 13q, 16q, or 17q was observed. However, tumors showing LOH of chromosomes 11p (chi 2 = 10.82, P less than 0.01) and 17p (chi 2 = 6.78, P less than 0.01) revealed a significantly higher incidence of metastasis to a regional lymph node(s) than tumors without LOH on these chromosomal arms. Furthermore, only four of 30 (13%) patients with tumors that retained both 11p and 17p had metastasis to a regional lymph node(s), compared with 24 of 32 (75%) patients with tumors that had lost both 11p and 17p. Analysis of LOH with markers on chromosomes 11p and 17p in a large number of tumors indicated that the peritelomeric region of each of these chromosomal arms contains a tumor suppressor gene that may be associated with tumor progression, particularly metastasis to a regional lymph node(s).

Disulfide bond structure of the atrial natriuretic peptide receptor extracellular domain: conserved disulfide bonds among guanylate cyclase-coupled receptors.

The disulfide bond structure of the extracellular domain of rat atrial natriuretic peptide (ANP) receptor (NPR-ECD) has been determined by mass spectrometry (MS) and Edman sequencing. Recombinant NPR-ECD expressed in COS-1 cells and purified from the culture medium binds ANP with as high affinity as the natural ANP receptor. Reaction with iodoacetic acid yielded no S-carboxymethylcysteine, indicating that all six Cys residues in NPR-ECD are involved in disulfide bonds. Electrospray ionization MS of NPR-ECD deglycosylated by peptide-N-glycosidase F gave a molecular mass of 48377.5+/-1.6 Da, which was consistent with the presence of three disulfide bonds. Liquid chromatography MS analysis of a lysylendopeptidase digest yielded three cystine-containing fragments with disulfide bonds Cys(60)-Cys(86), Cys(164)-Cys(213) and Cys(423)-Cys(432) based on their observed masses. These bonds were confirmed by Edman sequencing of each of the three fragments. No evidence for an inter-molecular disulfide bond was found. The six Cys residues in NPR-ECD, forming a 1-2, 3-4, 5-6 disulfide pairing pattern, are strictly conserved among A-type natriuretic peptide receptors and are similar in B-type receptors. We found that in other families of guanylate cyclase-coupled receptors, the Cys residues involved in 1-2 and 5-6 disulfide pairs are conserved in nearly all, suggesting an important contribution of these disulfide bonds to the receptor's structure and function.

Two hevein homologs isolated from the seed of Pharbitis nil L. exhibit potent antifungal activity.

Two antifungal peptides (Pn-AMP1 and Pn-AMP2) have been purified to homogeneity from seeds of Pharbitis nil. The amino acid sequences of Pn-AMP1 (41 amino acid0 residues) and Pn-AMP2 (40 amino acid residues) were identical except that Pn-AMP1 has an additional serine residue at the carboxyl-terminus. The molecular masses of Pn-AMP1 and Pn-AMP2 were confirmed as 4299.7 and 4213.2 Da, respectively. Both the Pn-AMPs were highly basic (pI 12.02) and had characteristics of cysteine/glycine rich chitin-binding domain. Pn-AMPs exhibited potent antifungal activity against both chitin-containing and non-chitin-containing fungi in the cell wall. Concentrations required for 50% inhibition of fungal growth were ranged from 3 to 26 micrograms/ml for Pn-AMP1 and from 0.6 to 75 micrograms/ml for Pn-AMP2. The Pn-AMPs penetrated very rapidly into fungal hyphae and localized at septum and hyphal tips of fungi, which caused burst of hyphal tips. Burst of hyphae resulted in disruption of the fungal membrane and leakage of the cytoplasmic materials. To our knowledge, Pn-AMPs are the first hevein-like proteins that show similar fungicidal effects as thionins do.

Reversibility from delayed hyperacute rejection in ABO-incompatible renal transplantation: histopathological findings of renal allograft biopsy.

ABO-incompatible renal transplantation (ABOIRTx) tend to lead to blood type antibody-mediated rejection, the so-called delayed hyperacute rejection (DHAR), which results in short-term graft loss. To clarify the accurate incidence and prognostic value of DHAR among ABOIRTx, we reviewed biopsy specimens obtained from ABOKTx allografts with abrupt dysfunction during the early period after transplantation. Among 74 ABOIRTx patients, 34 patients displayed allograft dysfunction within 14 days following transplantation. The biopsy specimens were classified based on the Banff schema. The pathological diagnosis of ABO blood type antibody-mediated humoral rejection (ABO-AMHR) was made by the following 3 findings: Specimens with all of above-mentioned findings were categorized as severe ABO-AMHR; those with at least one findings, were categorized as mild ABO-AMHR. All patients were treated with steroid pulse therapy and/or modification of other immunosuppressants. Group 1 consisted of severe ABO-AMHR (n = 6); group 2 consisted of mild ABO-AMHR (n = 5); group 3 consisted of acute cellular rejection (n = 3); group 4 consisted of recovery phase of ATN (n = 11); group 5 consisted of calcineurin inhibitor toxicity (n = 2); and group 6 consisted of normal histology (n = 5). One of 6 patients (16%) in group 1 lost the graft because of DHAR irreversible by antirejection and anticoagulation therapy. However, there has been no clear definition of histpathological criteria for DHAR after ABO-incompatible kidney transplantation. The definition must prognosticate whether the rejection process is reversible.

Baseline glomerular sclerosis influences morphological changes, but not level of serum creatinine.

The aim of this study was to investigate whether glomerular sclerosis (GS) at the time of engraftment affects subsequent morphology and clinical course of renal allografts. Eighty-one renal transplant recipients were recruited for this study. Protocol biopsies of the renal allografts were performed at engraftment, as well as at 1, 3, 5, and 7 years after transplantation. All cases were divided into 2 groups based on the presence of GS at engraftment, namely, non-GS and GS groups. Morphological changes in the renal allografts were graded from 0 to 3+ based on the severity of chronic allograft nephropathy (CAN) of the Banff classification based on 5 factors: percentage of GS, extent of interstitial fibrosis, tubular atrophy, arterial intimal thickening, and arteriolar hyalinosis. Furthermore, the level of serum creatinine (s-Cr) at each year was examined by recipient age and gender, donor age and gender, type of donor (living/cadaver), delayed graft function, acute rejection within 1 year after transplantation, mean blood pressure, and use of calcineurin inhibitors as well as the presence of GS at engraftment. The extent of GS at engraftment significantly correlated with donor age (P = .0038) but with a weak correlation coefficient. Although the severity of CAN developed gradually in both non-GS and GS groups, differences in morphological changes at engraftment between the 2 groups persisted throughout 7 years. Donor age and recipient gender influenced s-Cr significantly. In conclusion, the presence of GS at engraftment aggravates subsequent morphological changes and affects short-term but not long-term allograft prognosis.

Delivery of F2-excimer laser light by aluminum hollow fibers.

A hollow fiber composed of a glass-tube substrate and an aluminum thin film coated upon the inside of the tube delivers F2-excimer laser light. A smooth, aluminum thin film was deposited by using metal-organic chemical vapor deposition using dimethylethylamine:alane (DMEAA) as the precursor. It was shown that the transmission loss of the fiber with a 1.0-mm inner diameter was as low as 0.5 dB/m for the fiber with 1.0-mm diameter when the bore of the fiber is pressurized with an inert gas to remove the absorption of air. When the fiber is bent at the radius of 30 cm, the additional loss was 1.6 dB.

Complete covalent structure of porcine liver acylamino acid-releasing enzyme and identification of its active site serine residue.

The complete covalent structure of porcine liver acylamino acid-releasing enzyme (AARE) [EC3.4.19.1], which catalyzes the hydrolysis of an N-terminally acylated peptide to release an N-acylamino acid, has been established. On basis of the amino acid sequence deduced from the cDNA sequence of porcine liver AARE [Mitta, M. et al. (1989) J. Biochem. 106, 548-555], sequence determination has been achieved by automated Edman degradation of peptides generated by chemical or enzymatic cleavages of the reduced and S-carboxymethylated protein. Ion-spray mass spectrometry was also successfully used to confirm the amino acid sequences of the peptides determined above and to elucidate both the N-terminal blocking group and the status of half-cystine residues of this protein. The protein consists of 732 amino acid residues, and the N-terminal methionine residue is blocked by an acetyl group. All of 18 half-cystine residues of this protein were proved to exist as cysteine residues. A serine residue reactive with diisopropyl fluorophosphate (DFP) was also identified as Ser587 by preparation of the AARE labeled with tritiated DFP followed by isolation and sequence analysis of a radioactive peptide obtained from its endoproteinase Asp-N digest.

Methionine aminopeptidase from the hyperthermophilic Archaeon Pyrococcus furiosus: molecular cloning and overexpression in Escherichia coli of the gene, and characteristics of the enzyme.

A gene for a methionine aminopeptidase (MAP; EC 3.4.11.18), which catalyzes the removal of amino-terminal methionine from the growing peptide chain on the ribosome, has been cloned from the hyperthermophilic Archaeon, Pyrococcus furiosus, by a novel method effectively using its cosmid protein library, sequenced and expressed in Escherichia coli. The DNA sequence encodes a protein containing 295 amino acid residues with methionine at the N-terminus. From protein analyses of the recombinant protein expressed in E. coli, by using both amino acid sequence analysis from the N-terminus by automated Edman degradation and analyses of molecular masses of the peptides generated by two enzymatic cleavages performed independently, digestions with lysylendopeptidase and Endoproteinase Asp-N, with ionspray mass spectrometry, the primary structure of the protein has been elucidated to be completely identical with that deduced from its DNA sequence. Comparison of the amino acid sequence of P. furiosus MAP (P.f. MAP) with those of other MAPs from Eukarya and Bacteria showed that the protein has a high degree of sequence homology in the stretches surrounding the five cobalt-binding residues fully preserved in all of MAPs determined so far, but P.f. MAP belongs to Type II because it has an extra long insertion of about 60 amino acid residues between the fourth and fifth cobalt-binding ligands, similar to MAPs from human and rat, and to Met-AP2 from Saccharomyces cerevisiae, in comparison to Type I MAPs from Bacteria. Therefore, P.f. MAP seems to be rather close to those from Eukarya, although it is distinct in lacking the N-terminal extension of about 90-150 residues universally found in MAPs from Eukarya. These findings suggest that P.f. MAP is evolutionally located at the Eukarya-Bacteria boundary. The enzyme expressed in E. coli exhibits a considerable thermostability, with a half-life of approximately 4.5 h at 90 degrees C and an optimum temperature of around 90 degrees C.

Identification of the catalytic triad residues of porcine liver acylamino acid-releasing enzyme.

Acylamino acid-releasing enzyme (AARE) [EC 3.4.19.1] is a tetrameric serine protease, which belongs to the oligopeptidase family and specifically removes acetyl amino acids from N-terminally acetylated peptides. By using diisopropyl fluorophosphate, we previously identified one of the residues comprising the catalytic triad of this enzyme as Ser587 [Miyagi, M. et al. (1995) J. Biochem. 118, 771-779]. To elucidate the other two residues forming the catalytic triad of this new serine-type protease, wild-type and four mutant AAREs, in which each candidate residue of the catalytic triad deduced from sequence alignment with other oligopeptidases was substituted by site-directed mutagenesis, were expressed in Escherichia coli as fusion proteins with short peptide chains at both N- and C-termini of a subunit of porcine liver enzyme. All of the recombinant AAREs were estimated to have similar conformational and quaternary structures to the native porcine liver enzyme from their CD spectra and behavior on gel-filtration, but the mutants in which Ala587, Asn675, or Tyr707 was substituted for Ser587, Asp675, or His707, respectively, did not show detectable hydrolytic activity toward acetyl-L-methionyl L-alanine. These facts suggest that Ser587, Asp675, and His707 are essential residues for the AARE activity and comprise the catalytic triad of the enzyme in this order. Thus, AARE has been shown to have a protease-like domain in its C-terminal region, as do other proteins classified as members of the oligopeptidase family.

Lymphocyte isoforms of mouse p50 LSP1, which are phosphorylated in mitogen-activated T cells, are formed through alternative splicing and phosphorylation.

p50 is phosphorylated in mitogen-stimulated T cells, and translocated from the membrane to the cytosol after activation of protein kinase C. Sequence analysis of p50 revealed that it is identical with LSP1, a putative calcium-binding and actin-binding protein. lymphocyte form of p50 exhibits heterogeneity in the apparent molecular mass on SDS-PAGE, 50 and 52 kDa (pp50 and pp52), and each isoform exhibits heterogeneity in the isoelectric point, when examined by two-dimensional PAGE. When the two molecular mass variants of p50 were dephosphorylated with alkaline phosphatase, both isoforms showed the same apparent molecular mass of 50 kDa on SDS-PAGE, but could be distinguished by their distinct isoelectric points. Dephosphorylated pp50 (p50a) has an acidic pI compared with dephosphorylated pp52 (p50b). Comparison of the peptide maps of purified p50a and p50b on HPLC revealed that the difference was limited to one peptide peak. NH2-terminal sequence and mass spectrometric analyses of these peptides showed that the peptides derived from p50a and p50b had the same NH2-terminal amino acid sequence up to eight residues, but had distinct molecular masses, 5,533.4 and 6,318.6 Da, respectively. These data suggested that pp52 (p50b) is the product of the previously cloned cDNA and the reduction in the molecular mass of the p50a-derived peptide could be explained by deletion of six amino acid residues, EHLIRH or HLIRHQ.(ABSTRACT TRUNCATED AT 250 WORDS)