Employment status among non-retired cancer survivors in Japan.

Employed cancer patients confront some challenges as they attempt to return to work after treatment. We aimed to identify correlates of return to work for cancer survivors in Japan, with an emphasis on employment status. Participants were 260 patients (aged <65 years) who had received a cancer diagnosis ≥ 1 year previously and who were employed at the time of diagnosis. Participants completed questionnaires at consultations at any Regional Cancer Center Hospitals in Yamagata, Japan between 28 November 2011 and 9 December 2011. Logistic regression analysis was used to identify correlates of return to work. Data cross-tabulation was used to evaluate relationships to workplace and income-changes by employment status. A high proportion of patients (75.8%) had returned to work. Non-regularly employed survivors were less likely to return to work (odds ratio = 5.03; 95% confidence interval, 1.18-21.35). Individuals with poor health, advanced-stage tumours, of advanced age and women were significantly less likely to return to work. Only 52.8% of non-regular employees continued to be employed, and their income decreased by as much as 61.1%. Social and financial support policies should be organised based on more intensive study of employment circumstances.

Cystatin C as an index of cerebral small vessel disease: results of a cross-sectional study in community-based Japanese elderly.

BACKGROUND AND PURPOSE: Recent studies have shown that kidney dysfunction is associated with cerebral small vessel disease (SVD). Although creatinine-based estimating equations have been used as the standard measure for the evaluation of kidney function, the accuracy of these is limited in the elderly because of muscle mass decrease with aging. Cystatin C is a more useful measurement than creatinine-based estimating equations for evaluating kidney function, however, the relationship amongst cystatin C, cognitive dysfunction, and cerebral SVD has not been fully examined in community-based elderly. METHODS: We performed a cross-sectional study using MRI to determine the relationship amongst cystatin C, cognitive function, and cerebral SVD in a total of 604 community-based Japanese elderly. RESULTS: In this study, subjects with higher cystatin C levels tended to have more lacunas and higher grades of white matter lesions. Although a decline of the Mini-Mental State Examination (MMSE) scores was associated with SVD-related lesions, the relationship between the tertiles of cystatin C and mean MMSE scores was not statistically significant. In the logistic regression analysis, the association between cystatin C and SVD-related lesions was statistically significant, even after adjustment for conventional risk factors and high-sensitivity C-reactive protein. Furthermore, subjects with higher cystatin C levels accompanied with albuminuria had a greater risk for the presence of subclinical cerebral SVD than those with lower cystatin C levels without albuminuria. CONCLUSIONS: The present study suggests that there is a close relationship between cystatin C and subclinical cerebral SVD, independently of conventional risk factors, in community-based elderly.

Melittin-Like Peptides from the Shark-Repelling Defense Secretion of the Sole Pardachirus pavoninus.

Three ichthyotoxic peptides, pardaxins P-I to P-3, have been isolated from the defense secretion of the sole Pardachirus pavoninus. Pavoninins, the steroid glycosides with shark-repelling ability, had previously been isolated therefrom. Each pardaxin consists of 33 amino acid residues having a distinctly hydrophilic carboxyl terminal region and a predominantly hydrophobic remainder; the pardaxin is thus strongly surfactant. These peptides show marked physical and pharmacological similarities to melittin, the major active constituent of bee venom, yet they lack sequence homology. They are probably also responsible for the predator-repelling property of the sole.

Molecular cloning and expression of a novel adhesion molecule, SC1.

SC1, an integral membrane glycoprotein of 100 kd, is uniquely and transiently expressed on spinal cord motoneurons early in development and appears in peripheral neurons and several other tissues during development. SC1 has been purified by immunoaffinity techniques, and SC1 cDNA clones have been obtained by screening an E4 chick embryo phage expression library with a rabbit polyclonal antibody produced against purified SC1. The deduced protein sequence of 588 amino acids consists of a signal peptide, five immunoglobulin-like domains, a transmembrane region, and a short cytoplasmic tail. The sequence is most similar to MUC18, reported as a tumor progression marker in human melanoma. Transfection of SC1 cDNA into mammalian cells leads to cell surface expression of SC1 antigen and a subsequent increase in cell-cell adhesion. SC1 molecules bind to each other via a homophilic adhesion mechanism, independently of calcium or magnesium ions. SC1 may have a role in lateral motor column formation or neurite growth or fasciculation.

Amino acid sequence of the retinal binding site of squid visual pigment.

The retinylpeptides of visual pigments of two species of squid were identified in invertebrate visual pigments. Their primary structures were identical: H-Phe-Ala-Lys-Ala-Ser-Ala-Ile-His-Asn-pro-Hse(Met)-OH. The sequence was homologous to those of the corresponding region of other visual pigments, but the eighth amino acid, His, was found in squid visual pigments. In this experiment the retinylpeptides of eleven amino acid residues were isolated by monitoring the absorbance spectrum of the reduced retinal Schiff base without using radio-active [3H]retinal. This method is valid for the isolation and identification of retinylpeptides of other invertebrate visual pigments in which the chromophore is not exchangeable.

Purification and NH2-terminal amino acid sequences of human and rat kidney fatty acid omega-hydroxylases.

A cytochrome P-450 (P-450), designated P-450HK omega, has been isolated and purified from human kidney microsomes to a specific content of 13 nmoles of P-450/mg of protein. P-450HK omega showed an apparent molecular weight of 52,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Absolute spectra of the oxidized form indicated that this P-450 was largely in the low-spin state and partly in the high-spin state. It catalyzed the omega- and (omega-1)-hydroxylation of fatty acids such as laurate, myristate, and palmitate, with no activity toward prostaglandin A1, benzphetamine, 7-ethoxycoumarin, or 7-ethoxyresorufin. The first 35 NH2-terminal amino acid sequence of P-450HK omega had about 70% homology with those of rabbit kidney fatty acid omega-hydroxylases of the P-450 IVA gene subfamily, P-450ka-1, P-450ka-2, and P-450kd, except for four undetermined residues. Moreover, Western blot and immuno-inhibition studies showed that P-450HK omega reacted with an antibody against the rabbit kidney fatty acid omega-hydroxylase. The results suggest that P-450HK omega is a member of the same P-450 gene family (IVA subfamily) as the rabbit enzymes. In addition, the terminal sequence of P-450HK omega also showed 54% homology with that of P-450k-2, a fatty acid omega-hydroxylase from rat kidney microsomes. To our knowledge, this is the first time that a P-450 specific for fatty acid omega-hydroxylase activity has been isolated to homogeneity from human tissues.

Electrophysiologic effects of sodium channel blockade on anisotropic conduction and conduction block in canine myocardium: preferential slowing of longitudinal conduction by flecainide versus disopyramide or lidocaine.

OBJECTIVES: The purpose of this study was to determine the effects of sodium channel blockade on anisotropic excitation propagation in the intact canine left ventricle. BACKGROUND: Anisotropic ventricular conduction- electric conductivity dependent on the myocardial fiber direction-is one of the important mechanisms of ventricular arrhythmia. However, the effects of sodium channel blockade, especially the differential effect of a subclass of this agent, on the anisotropic properties remain unknown. METHODS: In 28 anesthetized, open chest dogs, a small cannula was inserted into the left anterior descending coronary artery. Saline (control), disopyramide, lidocaine or flecainide was infused selectively into the cannula. An array of 64 epicardial electrodes was placed on the anterior surface of the ventricle. Activation time (AT) was measured along the longitudinal (L) and transverse (T) directions. RESULTS: High dose flecainide (100 microg/kg body weight per min) delayed the AT along the L direction markedly (mean [+/-SE] 227 +/- 38%, p < 0.02) and mildly (121 +/- 10%, p < 0.02) along the T direction in regular beats (p < 0.007, L vs. T). Lidocaine and disopyramide did not show direction-dependent prolongation of the AT on regular beats. When examined on premature beats, AT was delayed, depending on the coupling interval and the fiber direction when saline, flecainide or lidocaine was infused. The conduction blocks along the L direction were observed in three of seven dogs on regular beats after flecainide and ventricular fibrillation ensued in two of these three dogs. CONCLUSIONS: A peculiar slowing of L conduction by flecainide may relate to the character of proarrhythmia.

Glibenclamide attenuates peaked T wave in early phase of myocardial ischemia.

OBJECTIVES: ECG peaked T wave appears during the early phase of myocardial ischemia, but the underlying mechanisms remain unknown. The purpose of this study was to elucidate the role of ATP-sensitive K+ channel (KATP) in this ECG change. METHODS: In 12 anesthetized, open-chest dogs, the sinus node was crushed and the right atrium was paced at a cycle length of 400 ms. The left anterior descending coronary artery was abruptly occluded for 60 s before (control) and 15 min after an intravenous infusion of vehicle (n = 6) or glibenclamide (1 mg/kg, n = 6), a blocker of KATP. Forty-eight epicardial electrograms were simultaneously recorded from the anterior surface of the left ventricle. The potentials at 40, 80 and 120 ms from the J point were measured, and these points corresponded to the early, middle and late phases of the T wave, respectively. RESULTS: During the control occlusion, T wave increased time-dependently and the maximal T-wave change was noted at the end of 60 s of coronary occlusion. The extents of T-wave elevation at the early, mid and late T phases were 5.5 +/- 0.5, 7.3 +/- 0.8 and 11.7 +/- 1.8 mV, respectively, and these T-wave elevations were significantly reduced by 33 +/- 21%, 59 +/- 12% and 63 +/- 13%, respectively, after the pretreatment with glibenclamide but not with its vehicle. The % reductions of mid and late T by glibenclamide were significantly larger than that of early T wave (P < 0.05). CONCLUSIONS: An abrupt coronary occlusion accompanied peaked T wave as an early ECG wave change. As the extent of this T-wave elevation was attenuated by glibenclamide, the ischemia-induced alteration of ventricular repolarization can partly (60%) be explained by the modification of KATP activation.

Peroxisomal acyl-coenzyme A oxidase multigene family of the yeast Candida tropicalis; nucleotide sequence of a third gene and its protein product.

We have determined the complete nucleotide sequence of gene POX2, which encodes one of the major peroxisomal polypeptides (PXPs) of Candida tropicalis. POX2 is linked to gene POX4, which codes for a subunit (PXP-4) of long-chain acyl-CoA oxidase. Southern blot analysis revealed that POX2 had a significant homology to POX4, and also to gene POX5 which encodes a subunit (PXP-5) of the isozyme of acyl-CoA oxidase. PXP-2, the protein product of POX2, was co-purified with PXP-4 from the isolated peroxisomes. PXP-2 itself was a flavoprotein and likely to form an equimolar complex with PXP-4, although its enzymatic activity was uncertain. POX2 corresponds to a single open reading frame of 724 amino acids and has no introns. The N-terminal sequence and the calculated Mr of the deduced polypeptide were consistent with those of isolated PXP-2. The primary structure was highly homologous to those of PXP-4 and PXP-5 in respect of the amino acid sequence and the hydropathy profile. We conclude that POX2 is a third gene of the peroxisomal acyl-COA oxidase multigene family.

Rapid methods for purification of human recombinant interleukin-5 (IL-5) using the anti-murine IL-5 antibody-coupled immunoaffinity column.

A large scale production of human recombinant IL-5 (hIL-5) was performed by way of recombinant DNA technology. In this study, we transfected Chinese hamster ovary cells with pdKCR-hIL-5gene-dhfr plasmid and selected a cell line, with the use of methotrexate, producing large amounts of hIL-5. The recombinant hIL-5 thus obtained induced IgM production of murine B cell leukemia BCL1, and its activity was inhibited by TB13 anti-mouse IL-5 monoclonal antibody. hIL-5 could be purified from the cell-free supernatants of the transfectants with high recoveries by using anti-mouse IL-5 antibody-coupled immunoaffinity column in combination with a gel permeation column chromatography. N terminal amino acid sequence analysis of purified hIL-5 revealed that a single amino-terminal amino acid (isoleucine) is detected and hIL-5 consists of 115 amino acid residues.

Left ventricular diastolic dysfunction in patients with bronchial asthma with long-term oral beta2-adrenoceptor agonists.

BACKGROUND: Long-term administration of oral beta(2)-adrenergic receptor agonists (beta(2)-AG) in patients with bronchial asthma (BA) causes disastrous events such as sudden death and heart attack. However, long-term effects of beta(2)-AG on cardiac function have not been previously quantified. METHODS: Seventy-four patients with BA with regular long-term use of oral beta(2)-AG (group A) and 69 patients with BA without beta(2)- AG (group B) were examined in medical records of outpatient clinics from 1985 to 1999. In the prospective study, echocardiography was performed in 48 consecutive patients from January to April 1999. There were 26 patients with regular oral use of beta(2)-AG (group a) and 22 patients without beta(2)-AG (group b). Twenty-one age-matched normal volunteers without heart or pulmonary diseases were used as control subjects (group c). Oral beta(2)-AG was withdrawn from remedies in 11 patients of group a, and echocardiographic studies were repeated 2 weeks after its cessation. RESULTS: Events related to heart failure were more frequently seen in group A than in group B (14% vs 1%, P <.01). The echocardiographic study showed that indexes of left ventricular diastolic but not systolic function were significantly deteriorated in group a, along with a markedly reduced level of plasma norepinephrine concentration (P <.05 vs groups b and c). When heart rate was adjusted to 90 beats/min during isoproterenol infusion, left ventricular diastolic function remained deteriorated in group a (P <.05 vs groups b and c). In 11 patients of group a, the cessation of beta(2)-AG for 2 weeks resulted in an improvement of left ventricular diastolic function and in an increase of plasma norepinephrine level (P <.01). CONCLUSIONS: Long-term use of oral beta(2)-AG impaired left ventricular diastolic function in patients with BA, and the cessation of beta(2)-AG reversed diastolic pump performance to the normal level.

Isointegral analysis of body surface maps for the assessment of location and size of myocardial infarction.

To estimate the location and size of myocardial infarction (MI), an isointegral mapping technique was adopted from among various body surface electrocardiographic mapping techniques. QRS isointegral and departure maps were made in 35 patients with MI. These patients were separated into 3 groups, based on the location of MI: anterior, inferior, and anterior plus inferior. The severity and location of MI were estimated by thallium-201 myocardial perfusion imaging and the degree of scintigraphic defect was represented by a defect score. The extent of MI was expected to be reflected on the QRS isointegral maps as a distribution of negative QRS complex time-integral values. However, the extent and the location of MI were hardly detectable by the original maps. A departure mapping technique was then devised to observe the distribution of departure index on the body surface. Particular attention was given to the area where the departure index was less than -2, and this area was expected to reflect the location and size of specific abnormality of isointegral map due to MI. There were strong correlations between departure area and defect score in the anterior and inferior MI cases (r = 0.88 and r = 0.79, respectively). However, patients with anterior MI plus inferior MI showed no such correlation. Q-wave mapping was compared with QRS isointegral mapping, and QRS isointegral mapping was found to be more accurate in the estimation of the location and size of MI than Q wave mapping. Thus, QRS isointegral mapping, especially departure mapping, is more useful and convenient for detecting the location and size of MI than methods such as isopotential and Q wave mapping.

Isolation of a new form of cytochrome P-450 with prostaglandin A and fatty acid omega-hydroxylase activities from rabbit kidney cortex microsomes.

Two different forms of cytochrome P-450, highly active in the omega-hydroxylation of prostaglandin A, and the omega- and (omega-1)-hydroxylation of fatty acids (P-450ka-1 and P-450ka-2), have been purified from kidney cortex microsomes of rabbits treated with di(2-ethylhexyl)-phthalate. On the basis of the peptide map patterns and NH2-terminal amino acid sequence, P-450ka-1 was determined to be a new form of omega-hydroxylase cytochrome P-450, whereas P-450ka-2 is identical to P-450ka reported earlier. The first 20 NH2-terminal amino acid sequence (ALNPTRLPGSLSGLLQVAGL) and (ALSPTRLPGSFSGFLQAAGL) of P-450ka-1 and P-450ka-2 showed 90 and 80% homology with that of the lung prostaglandin omega-hydroxylase, respectively, suggesting that these three cytochromes P-450 are members of the same omega-hydroxylase cytochrome P-450 gene family.

Site-directedly mutated human cytochrome c which retains heme c via only one thioether bond.

Although Cys-14 (human numbering) of cytochrome c was conserved during its molecular evolution and it is supposed to be essential for most cytochromes c to retain heme c via two thioether bonds, a site-directedly mutated human cytochrome c which has an alanine residue at this position and only one thioether bond through Cys-17 turns out to be functional. This shows that Cys-14 is not essential. The absorption spectrum of the atypical cytochrome c is red shifted, and similar to those of Euglena and Crithidia cytochromes c, which also have only one thioether bond [Pettigrew, G.W., Leaver, J.L., Meyer, T.E., & Ryle, A.P. (1975) Biochem. J. 147, 291-302].

Purification and characterization of two forms of cytochrome P-450 with omega-hydroxylase activities toward prostaglandin A and fatty acids from rabbit liver microsomes.

Two forms of cytochrome P-450 (P-450), designated as P-450LPGA omega 1 and P-450LPGA omega 2, have been purified to specific contents of 17.9 and 11.1 nmol P-450/mg protein, respectively, from liver microsomes of rabbits treated with di(2-ethylhexyl)phthalate (DEHP), a peroxisomal proliferator. The purified P-450LPGA omega 1 and P-450LPGA omega 2 were found to have apparent molecular weights of 52,500 and 53,000, respectively. They showed absorption maxima at 451 and 450 nm in the carbon monoxide-difference spectra for their reduced forms, respectively. The two P-450s both efficiently catalyzed the omega-hydroxylation of prostaglandins A1 (PGA1) and A2 (PGA2), as well as the omega- and (omega-1)-hydroxylation of fatty acids such as laurate, myristate, and palmitate. In a reconstituted system, various metal ions such as Na+ and Mg2+ stimulated these reactions. The P-450s exhibited no detectable activity toward several xenobiotics tested. The two P-450s showed different peptide map patterns following limited proteolysis with Staphylococcus aureus V8 protease or papain. The NH2-terminal amino acid sequences (ALNPTRLPGSLSGLLQVAGL and ALSLTRLPGSFSGFLQAxGLLGLLL) of P-450LPGA omega 1 and P-450LPGA omega 2 were identical at 18/20 and 19/24 positions with that of the lung prostaglandin omega-hydroxylase from pregnant rabbits, respectively. An antibody against P-450LPGA omega 2 recognized a 52,000-53,000 molecular weight protein(s) in rabbit liver microsomes. The intensity of the immunoblot was significantly increased in liver microsomes from rabbits treated with DEHP, but not with phenobarbital or 3-methylcholanthrene.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on phospholipase A inhibitor in blood plasma. I. Purification and characterization of phospholipase A inhibitor in bovine plasma.

Phospholipase A inhibitor was found in bovine, human and porcine plasma. The inhibitor was purified about 300-fold from bovine plasma by ammonium sulfate fractionation, DEAE-cellulose chromatography, Sephadex G-200 gel filtration and anti-BSA antibody-agarose column chromatography to remove albumin. The purified material was homogeneous as judged by immunoelectrophoresis and 0.7% agarose-2% polyacrylamide gel electrophoresis. The inhibitor suppressed not only rat and human plasma phospholipase A2 activity, but also purified Mamushi (Agkistrodon halys blomhoffi) venom phospholipase A2-II. Bovine plasma inhibitor was shown to be a lipoprotein containing phosphatidylcholine, sphingomyelin, cholesterol ester, and triacyl glycerol as major lipid components. The molecular weight of the native inhibitor was nearly the same as that of bovine plasma high density lipoprotein (HDL) when determined by the gel filtration method. The molecular weights of two subunits of the inhibitor observed on polyacrylamide gel electrophoresis in the presence of SDS were about 10K and 42K. The anti-inhibitor antiserum obtained from rabbits immunized with the highly purified inhibitor cross-reacted with bovine plasma alpha-lipoprotein (HDL). The lipid composition of the inhibitor was similar to that of HDL, but apoinhibitor and apoHDL were different in molecular weight and solubility in various buffers.

Reactive sulfhydryl groups of sarcoplasmic reticulum ATPase. I. Location of a group which is most reactive with N-ethylmaleimide.

Ca2+-Transporting ATPase of rabbit skeletal muscle sarcoplasmic reticulum contains several SH groups which are reactive with N-ethylmaleimide (MalNEt) at pH 7.0. The location of the one which is most reactive with MalNEt (SHN, Kawakita et al. J. Biochem. 87, 609 (1980)) was identified on the amino acid sequence of the ATPase. SHN was labeled by reacting sarcoplasmic reticulum membranes with [14C] MalNEt to a labeling density of 1 mol/mol ATPase. [14C]MalNEt-labeled membranes were digested with thermolysin and 14C-labeled SHN peptides were fractionated by Sephadex LH-20 chromatography to give two major peaks of radioactivity. [14C]-MalNEt-labeled peptides were further purified to homogeneity by C18-reversed phase HPLC. Two radioactive peptides containing modified cysteine (Cys), Leu-Gly-Cys-Thr-Ser and Val-Cys-Lys-Met, were finally obtained in roughly equal amounts and in reasonable recovery. Both of these sequences were found in the amino acid sequence of Ca2+-transporting ATPase (Brandl et al. Cell 44, 597 (1986)), and Cys344 and Cys364 were identified as the targets of MalNEt-modification. Thus, 0.5 mol/mol ATPase of each Cys residue actually reacted rapidly with MalNEt under the conditions leading to SHN-modification. Modification of either one with MalNEt may negatively affect the reactivity of the other. Both of the highly reactive SH groups are located in the neighborhood of Asp351, the phosphorylation site of ATPase.

Purification and characterization of hepatic microsomal prostaglandin omega-hydroxylase cytochrome P-450 from pregnant rabbits.

Prostaglandin omega-hydroxylase, designated as cytochrome P-450 LPG omega (P-450 LPG omega), has been purified, to a specific content of 15 nmol of cytochrome P-450/mg of protein, from liver microsomes of pregnant rabbits. The purified P-450 LPG omega was found to be homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and to have an apparent molecular weight of 52,000. The enzyme showed a maximum at 450 nm in the carbon monoxide (CO)-difference spectrum for its reduced form. This cytochrome P-450 efficiently catalyzed the omega-hydroxylation of prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), prostaglandin F2 alpha (PGF 2 alpha), prostaglandin A1 (PGA1), and prostaglandin A2 (PGA2), as well as the omega- and (omega-1)-hydroxylation of myristate and palmitate, in a reconstituted system containing cytochrome P-450, NADPH-cytochrome P-450 reductase, phospholipid, and cytochrome b5. Various monovalent and divalent cations further stimulated these reactions in the presence of cytochrome b5. In addition, the reactions were also markedly enhanced by various organic solvents, such as ethanol and acetone. This cytochrome P-450 showed no detectable activity toward several xenobiotics tested. P-450 LPG omega was very similar or identical to the pulmonary prostaglandin omega-hydroxylase (P-450p-2) (Yamamoto, S., Kusunose, E., Ogita, K., Kaku, M., Ichihara, K., & Kusunose, M. (1984) J. Biochem. 96, 593-603) in its molecular weight, absorption spectra, catalytic activity, peptide mapping pattern, and N-terminal amino acid sequence. However, P-450 LPG omega was more unstable than P-450p-2 on storage. In sharp contrast to P-450p-2, P-450 LPG omega was not induced by progesterone.

Purification and characterization of human microsomal dipeptidase.

Human microsomal dipeptidase (MDP, formerly referred to as dehydropeptidase-I or renal dipeptidase) [EC 3.4.13.11] was solubilized from the membrane fraction of kidney by treatment with octyl-beta-D-glucoside and purified by a procedure including ion exchange chromatography and affinity chromatography on cilastatin-immobilized Sepharose. The purified human MDP was found to be homogeneous on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The apparent molecular weight (Mr) was estimated by SDS-polyacrylamide gel electrophoresis under non-reducing conditions to be 130 kDa, comprising a homodimer of two subunits. After treatment with endoglycosidase F, human MDP showed a single band with an apparent Mr of 42 kDa on SDS-polyacrylamide gel electrophoresis. Human MDP was found to bind to Con A-Sepharose and the activity was eluted with methyl-alpha-D-mannopyranoside, suggesting that human MDP is a glycoprotein. We also examined the substrate specificity of human MDP and found that human MDP catalyzed the hydrolysis of S(substituent)-L-cysteinyl-glycine adducts such as L-cystinyl-bis(glycine) and S-N-ethylmaleimide-L-cysteinyl-glycine, as well as the conversion of leukotriene D4 to leukotriene E4. These results suggest that MDP might play an important role in the metabolism of glutathione and leukotriene.

Purification and characterization of two forms of fatty acid omega-hydroxylase cytochrome P-450 from rabbit kidney cortex microsomes.

We have previously reported the isolation of two forms of cytochrome P-450 (P-450) with omega-hydroxylase activities toward prostaglandin A (PGA) and fatty acids, designated as P-450ka-1 and P-450ka-2, from kidney cortex microsomes of rabbits treated with di(2-ethylhexyl)phthalate [Kusunose, E. et al. (1989) J. Biochem. 106, 194-196]. In the present work, we have purified and characterized two additional forms of rabbit kidney fatty acid omega-hydroxylase, designated as P-450kc and P-450kd. The purified P-450kc and P-450kd had specific contents of 13 and 16 nmol of P-450/mg of protein, with apparent molecular weights of 52,000 and 55,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively. Both the forms showed absorption maxima at 450 nm in the carbon monoxide-difference spectra for their reduced forms. These P-450s efficiently catalyzed the omega- and (omega-1)-hydroxylation of fatty acids such as caprate, laurate, myristate, and palmitate, in a reconstituted system containing P-450, NADPH-P-450 reductase, and phosphatidylcholine. Cytochrome b5 stimulated the reactions to only a slight extent. They had no detectable activity toward PGA and several xenobiotics tested. The two P-450s showed different peptide map patterns after limited proteolysis with papain or Staphylococcus aureus V8 protease.(ABSTRACT TRUNCATED AT 250 WORDS)