Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lysate of the glycogen-induced macrophages in rat peritoneal exudate was fractionated by centrifugation and extraction into a water extract, 1 M KCl extract and residue fractions. Approximately 50% of the neutral protease activity toward casein in the lysate was recovered in the KCl extract fraction, which was practically devoid of acid protease, cathepsin D. The pH optimum of the neutral protease toward casein and urea-denatured hemoglobin was pH 8.5. The activity was inhibited strongly by DFP or chymostatin and only partially by HgCl2 or PCMB. Addition of a salt to the reaction medium caused enhancement of the activity with an optimum concentration of 0.25 M: KCl, KBr, KI, NaCl, NaBr, NaI, and MgCl2 were all almost equally effective. When the enzyme preparation was filtered through a column of Sephadex G-75 gel in the presence of 1 M KCl, a larger molecular weight fraction at the void volume was obtained in addition to a smaller molecular weight fraction showing a caseinolytic activity insensitive to KCl concentration. The former was found to have a specific inhibitory effect on the latter activity.
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PMID:The occurence of a neutral protease and its inhibitor in rat peritoneal macrophages. 1 54

The specificity and mode of action of an acid proteinase (EC 3.4.23.6) from Aspergillus saitoi were investigated with oxidized B-chain of insulin, angiotensin II and bradykinin. Further purification of acid proteinase was performed with N,O-dibenzyloxycarbonyl-tyrosine hexamethylene-diamino-Sepharose 4B affinity chromatography and isoelectric focusing. The purified enzyme was free of any other proteolytic activity demonstrated in Asp. saitoi. Acid proteinase from Asp. saitoi hydrolyzed primarily two peptide bonds in the oxidized B-chain of insulin, the Leu(15)-Tyr(16) bond and the Phe(24)-Phe(25) bond. Additional cleavages of the bonds His(10)-Leu(11), Ala(14)-Leu(15) and Tyr(16)-Leu(17) were also noted. Primary splitting sites at Leu(15)-Tyr(16) and Phe(24-)-Phe(25) with acid proteinase from Asp. saitoi were identical with those reported in the work of cathepsin D (EC 3.4.23.5) from human erythrocyte. Hydrolysis of angiotensin II was observed at the Tyr(4)-Ile(5) bond. In conclusion, peptide bonds which have a hydrophobic amino acid such as phenylalanine, tyrosine, leucine and isoleucine in the P'1 position (as defined by Berger and Schechter, [29]) are preferentially cleaved by the trypsinogenactivating acid proteinase from Asp. saitoi.
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PMID:Purification of an acid proteinase from Aspergillus saitoi and determination of peptide bond specificity. 2 99

Rat embryo fibroblasts, grown in Eagle's MEM with 10% serum, showed a rapid increase in autophagic vacuoles when placed in MEM with 0-1% serum. Concurrent with this response, degradation of cellular proteins showed a 2-fold increase. We did not find any increases in cathepsin D, beta-glucuronidase, beta-galactosidase, and beta-glucosidase, or proteolytic activity of cell homogenates at pH 3.7 towards endogenous substrates. Homogenates prepared in 250 mM sucrose at pH 7.0 showed a 40% increase in protein breakdown. These data support the hypothesis that the induced increase in proteolysis, characteristic of cells placed in a nutritionally deficient medium, is effected by an activated vacuolar apparatus (lysosomes and autophagic vacuoles). We suggest, however, that this mechanism is distinct from normal protein turnover in the cell, but can be rapidly induced by appropriate alterations in the cellular environment. Finally, this induced proteolytic mechanism is not dependent upon an increase in lysosomal enzymes, but rather a structural alteration within the cell which effects a transfer of cellular proteins into the vacuolar apparatus.
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PMID:Role of the vacuolar apparatus in augmented protein degradation in cultured fibroblasts. 2 52

1. The procedure of Barrett [(1973) Biochem. J.131, 809-822] for isolating cathepsins B and D from human liver was modified for use with rat liver and skeletal muscle. The purified enzymes appeared to be similar to those reported in other species. 2. Sephadex G-75 chromatography of concentrated muscle extract resolved two peaks of cathepsin B inhibitory activity, corresponding to molecular weights of 12500 and 62000. 3. The degradation of purified myofibrillar proteins by cathepsins B and D was clearly demonstrated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. After incubation with enzyme, the polypeptide bands representing the substrates decreased in intensity and lower molecular weight products appeared. 4. Cathepsins B and D, purified from either rat liver or skeletal muscle, were shown to degrade myosin, purified from either rabbit or rat muscle. Soluble denatured myosin was degraded more extensively than insoluble native myosin. Degradation by cathepsin B was inhibited by lack of reducing agent, or by myoglobin, iodoacetic acid and leupeptin, but not by pepstatin. The same potential modifiers were applied to cathepsin D, and only pepstatin produced inhibition. 5. Rat liver cathepsin B had a pH optimum of 5.2 on native rabbit myosin. The pH optimum of cathepsin D was 4.0, with a shoulder of activity about 1pH unit above the optimum. 6. Rat liver cathepsins B and D were demonstrated to degrade rabbit F-actin at pH5.0, and were inhibited by leupeptin and pepstain, respectively. 7. The degradation of myosin and actin by cathepsin D was more extensive than that by cathepsin B.
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PMID:Degradation of myofibrillar proteins by cathepsins B and D. 2 66

1. Isorenin was purified 2000-fold from rat brain by a simple 3-step procedure involving affinity chromatography on pepstatinyl-Sepharose, The preparation appears as a homogenous protein in analytical polyacrylamide gel electrophoresis. Sodium dodecyl sulfate gel electrophoresis indicated an apparent molecular weight of 45 000. Isoelectric focusing separated isoenzymes with isoelectric points at pH 5.45, 5.87, 6.16 and 7.05. 2. The enzyme generates antiotensin I from tetradecapeptide (pH optimum 4.7) and from sheep angiotensinogen (pH optima 3.9 and 5.5). The rate of angiotensin I formation from tetradecapeptide was 30 000 times higher than that from sheep angiotensinogen. The enzyme has acid protease activity at pH 3.2 with hemoglobin as the substrate and pepstatin is a potent inhibitor of the enzyme with a Ki of less than 10(-9) M. 3. The properties of the enzyme strongly suggest that it is identical with cathepsin D.
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PMID:Purification and partial characterization of rat brain acid proteinase (isorenin). 2 50

Two kinds of cathepsin D were found in Japanese monkey lung and were named cathepsins D-I and D-II. Cathepsin D-I was partially purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. It had properties common to other ordinary cathepsins D in terms of the elution position from a DEAE-cellulose column at pH 8.0, the pH-dependence of activity toward acid-denatured hemoglobin, and the molecular weight of 35,000 as determined by Sephadex G-100 gel filtration. On the other hand, cathepsin D-II was purified about 1,000-fold by a combination of ammonium sulfate fractionation and column chromatographies on DEAE-cellulose and Sephadex G-100. It was a very acidic protein as judged from its elution position from a DEAE-cellulose column at pH 8.0, and the high mobility toward the anode on disc gel electrophoresis at pH 8.6. Its molecular weight was determined to be 35,000 by Sephadex G-100 gel filtration and 39,000 by SDS-polyacrylamide gel electrophoresis. It was optimally active at pH 2.8 against acid-denatured hemoglobin as a substrate, showing 80% of the optimal activity at pH 1.0, and almost no activity above pH 4.0. This pH-profile of activity was similar to that of monkey pepsin C (gastricsin). It did not hydrolyze N-acetyl-L-phenylalanyl-3,5-diiodo-L-tyrosine, a synthetic substrate for pepsin, but was inhibited by a series of pepsin inhibitors such as pepstatin, 1,2-epoxy-3-(p-nitrophenoxy)propane, p-bromophenacyl bromide, and diazoacetyl-DL-norleucine methyl ester, although the diazo reagent was a rather weak inhibitor of the enzyme. The amino acid composition of cathepsin D-II was found to be fairly different from those of other cathepsins D. However, it showed a striking resemblance to that of Japanese monkey pepsinogen C, suggesting some evolutionary relationship between them.
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PMID:The structure and function of acid proteases. VIII. Purification and characterization of cathepsins D from Japanese monkey lung. 2 23

The enzymatic activity of five acid hydrolases: acid phosphatase, arylsulfatase A, deoxyribonuclease, beta-glucuronidase, and cathepsin D, was assayed in fetal (fifteenth and eighteenth days of pregnancy) and neonatal (Days 0, 5, 10, and 15 post-partum) mouse liver. With the exception of cathepsin D, the activity increased around birth to levels varying according to the enzyme. Histochemical observations of other authors appear to justify, at least in part, the present results, which indicate that late days of fetal development and early neonatal life may constitute a transitional stage to full lysosomal enzyme functionality of the adult organ. The livers of the mothers were also assayed for the same enzymes. Each activity showed a peculiar pattern which was, in turn, different from that found in the liver of the litter for the same enzyme, probably as a cause of the metabolic requirement of the gland. The hypothesis that the lysosomes are heterogeneous in their enzyme composition is suggested by the variety of enzymatic patterns found in the liver of the litters and their mothers.
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PMID:The development of lysosomal apparatus. I. Lysosomal enzyme activities in the liver of mice at perinatal stages and those of their mothers. 2 3

Cryptorchidism of the mature rat testis led to degeneration of the seminiferous tubules and changes in enzyme patterns and activities. Spermatogenic stages 1-4, containing pachytene primary spermatocytes in late meiotic prophase, and stage 5, containing recently formed round spermatids, were damaged by 48 h. Within 96 h stages showed a loss of germinal cells into the lumen and this was almost complete by 192 h. Acid phosphatase showed increased histochemical activity in the basal area of the seminiferous tubule up to 96 h of cryptorchidism, and at 192 h much of the activity was located in large lipidcontaining bodies within the remaining seminiferous epithelium. Total and free biochemical acid phosphatase decreased during cryptorchidism in parallel with cell loss; there were no significant changes in total cathepsin D activity but free enzyme activity was increased throughout the experimental period indicating increased lability of lysosomes in the Sertoli cell. Lactate dehydrogenase activity was mainly tubular but succinate dehydrogenase also showed interstitial activity. Lipoamide dehydrogenase (NADH) was found mainly in the interstitium. During cryptorchidism both lactate and succinate dehydrogenase activity decreased in the tubules parallel to the loss of germinal cells, whereas lipoamide dehydrogenase (NADH) activity increased in both interstitial and tubular areas. It is suggested that the initial lesion in the seminiferous epithelium, produced by cryptorchidism is in the Sertoli cell and that germ cell damage may result from reduced function of the Sertoli cell.
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PMID:The effect of cryptorchidism on the quantitative histology, histochemistry and hydrolytic enzyme activity of the rat testis. 2 15

In a continuing study of the physiological role of protein breakdown in the hypothalamus, acid proteinase from bovine hypothalamus was purified about 1000-fold. The molecular weight of the enzyme was approximately 50,000. Masimal activity against hemoglobin was obtained at pH 3.2-3.5; serum albumin was split much more slowly. Hypothalamus acid proteinase was partially inhibited by beta-phenyl pyruvate, or benzethonium Cl, and was completely inhibited by low concentrations of pepstatin. This proteinase splits somatostatin, substance P, and analogs of substance P. The probable sites of enzyme action on these peptides were determined by the end group dansyl technique. The enzyme, most likely cathepsin D, may play an important role in the formation and breakdown of peptide hormones in the hypothalamus.
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PMID:Acid proteinase of hypothalamus. Purification, some properties, and action on somatostatin and substance P. 2 91

A neutral proteinase secreted by rabbit synovial fibroblasts in parallel with specific collagenase was partially purified by ion-exchange chromatography. At pH 7.6 this proteinase degraded 35S-labelled bovine nasal proteoglycan and azo-casein. The enzymic activity was inhibited by EDTA, 1,10-phenanthroline and serum, whereas di-isopropyl phosphorofluoridate and soya-bean trypsin inhibitor had little effect. By gel filtration the apparent mol.wt. of the enzyme was 25000. The fibroblast neutral proteinase was compared with the proteoglycan-degrading neutral proteinases of rabbit polymorphonuclear-leucocyte granules. Two distinct activities were found in the granules: one was inhibited by soya-bean trypsin inhibitor and the other by EDTA. The proteoglycan-degrading proteinases of rabbit fibroblasts and polymorphonuclear leucocytes at acid pH also were examined. Both cathepsin D and a thiol-dependent proteinase contributed to the degradation of proteoglycan at pH 4.5.
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PMID:Proteoglycan-degrading enzymes of rabbit fibroblasts and granulocytes. 3 Apr 51


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