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)

Two papain inhibitors, I1 and I2, from rat skin extract were purified by affinity chromatography on KSCN-modified papain-agarose gel and by gel filtration on Sephadex G-100. I1 had a molecular weight of 74 000, a pI of 4.6, and it contained 4% of carbohydrates. I1 inhibited papain, ficin, bromelain, rat skin benzoylarginine-2-naphthylamide hydrolase, and to a minor extent, rat skin cathepsin C and bovine trypsin. Bovine chymotrypsin or rat skin cathepsin D were not inhibited and benzoylarginine-2-naphthylamide hydrolase was inhibited only at alkaline pH. An inhibitor corresponding to I1 was present in various rat tissues and also in serum. A similar inhibitor was present in the skin of cat, rabbit, guinea pig, and man. I2 had a molecular weight of 13 400, a pI of 4.9 and it contained no carbohydrates. I2 inhibited all thiol proteases tested, but not trypsin, chymotrypsin, or rat skin cathepsin D. I2 formed an equimolar complex with papain and benzoylarginine-2-naphthylamide hydrolase. I2 was present in rat skin, muscle, lung, and small intestine, but not in kidney, liver, or serum. A similar inhibitor was found in skin extracts of cat, rabbit, guinea pig, and man.
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PMID:Purification and properties of two protease inhibitors from rat skin inhibiting papain and other SH-proteases. 1 95

The protease activity in guts of Ornithodoros tholozani females was studied in vitro. The intracellular protease in Ornithodoros tholozani guts has a pH optimum of about 3.0. Hemoglobin is the preferred substrate, and bovine serum albumin is digested very slowly. In this respect the protease resembles cathepsin D. Unfed ticks contain a small amount of protease in the gut. After feeding the level of protease increases gradually for several days until peak protease activity is attained. The level of gut protease activity depends on the size of the blood meal taken and on the interval after feeding. After a period of peak protease activity, the level of protease declines. The level of gut protease in unmated females (kept at 27 degrees C) did not reach prefeeding levels within 100 days. The level of gut proteolytic activity, as determined by in vitro protease assays, does not reflect the degree of blood digestion which takes place in vivo. After a period of rapid digestion, lasting for about two weeks, the undigested part of the blood meal remains unchanged in the lumen of the gut. At that time the gut tissue contains considerable levels of protease, which can be demonstrated by in vitro assays. Presumably, the protease remains active inside the gut cells, although the uptake of hemoglobin from the gut lumen has ceased. The results are compared to those obtained in other tick species.
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PMID:Protease activity in female Ornithodoros tholozani ticks. 1 32

Exogenous hen lysozyme or endogenous rat lysozyme labeled with 131I was intravenously injected to rats with the same dosage, respectively, and the uptake and degradation of injected 131I-labeled rat lysozyme in liver and kidney were studied in comparison with those of 131I-labeled hen lysozyme. 1. Although the serum levels of both enzymes injected were almost indentical during the first 6 h, the liver uptake of 131I-labeled hen lysozyme was 2.2-fold more than that of 131I-labeled rat lysozyme at the peak time of 5 min after injection. The uptake and clearance of 131I-labeled rat lysozyme in the kidney were exclusively slow as compared with those of 131I-labeled hen lysozyme. 2. The intracellular distribution in the liver and kidney were examined by the differential centrifugation after injection of each lysozyme. The protein-bound radioactivity of each subcellular fraction was found to be the highest in the 12 000 X g (10 min) fraction in the liver and the 19 600 X g (20 min) fraction in the kidney. The relative specific activity of 12 000 X g fraction of the liver after injection increased with the time lapse. On the other hand, the relative specific activity of 105 000 X g (1 h) fraction of the liver attained a maximum within 5 min after injection and thereafter decreased. It was assumed that the mechanism of the uptake of injected 131I-labeled rat lysozyme in the liver and kidney was similar to that of 131I-labeled hen lysozyme. 3. The degradation of exogenous or endogenous lysozyme in subcellular particles was examined. From the effect of pH, activator and inhibitor on the degradation, the proteolytic enzyme to degrade the injected 131I-labeled hen lysozyme was indicated to be mainly cathepsin BL, with the optimal pH of about 5.0, and the injected 131I-labeled rate lysozyme was mainly degraded by cathepsin D, with the optimal pH of about 3.5 The in vitro degradation of exogenous and endogenous lysozymes showed a tendency similar to the in vivo clearance from the liver and kidney.
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PMID:Studies on biotransformation of lysozyme. III. Comparative studies on biotransformation of exogenous and endogenous lysozyme in rats. 1 53

The cellular basis of the age-related decline in the functional capacity of many mammalian organs is still poorly understood. In this paper, the rat liver is presented as a promising model for studying cellular phenomena underlying organ ageing. The recent development of methods for isolation and purification of parenchymal, Kupffer and endothelial cells from the rat liver makes possible the comparison of functional and metabolic changes in the intact liver with changes in distinct liver cell classes isolated from rats of various age groups. An attempt has been made to correlate age changes in some important liver-specific functions, such as bromsulophthalein uptake and albumin synthesis, at the organ and at the cellular level. To compare cellular ageing phenomena in long-lived cells (parenchymal cells) and short lived cells (Kupffer and endothelial cells) from the same organ, the role of lysosomes in cellular ageing processes was investigated, with secial reference to the functioning of the lysosomal enzyme cathepsin D. The specific cathepsin D activity in Kupffer cells was abour 3 times higher than in endothelial cells and about 20 times higher than in parenchymal cells. The enzyme activity in the latter cell type showed a significant increase with age.
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PMID:Model systems for studies on cellular basis of organ ageing. 1 45

Mouse leukemia L1210 cells contain lysosomes, but cathepsin D, a typical lysosomal enzyme, has an unusual localization. After fractionation of homogenates of L1210 cells by isopycnic density gradient centrifugation, most of the activity for all of the acid hydrolases studied, except cathepsin D, is sedimentable and shows a similar density distribution around a peak having a modal density of 1.16. In contrast, much more of the total activity for cathepsin D is not sedimentable, while the sedimentable activity has a distribution around a peak at a higher density of 1.18. After chromatography on Sephadex G-100 of cell extracts, two molecular weight forms of cathepsin D are found. One has an apparent molecular weight of approx. 45,000, similar to rat liver cathepsin D, while the apparent molecular weight of the second form is approx. 95,000. Both forms are 4-5 times more active than rat liver cathepsin D. The high molecular weight L1210 cathepsin D converts to the low molecular weight form with no loss in activity after treatment with beta-mercaptoethanol. In all respects the unusual intracellular localization and molecular weight forms of cathepsin D in mouse leukemia L1210 cells are similar to the situation found for rat thoracic duct lymphocytes.
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PMID:Cathepsin D of mouse leukemia L1210 cells. Unusual intracellular localization and biochemical properties. 1 6

1. The distribution of acid protease activity in various tissues of Japanese monkey (Macaca fuscata fuscata) was investigated with hemoglobin as a substrate at pH 3.0. The activity per protein weight in crude extracts was highest in spleen and lung, and decreased in the order: spleen, lung greater than kidney, testis greater than brain greater than liver, placenta greater than thyroid gland, muscle. The activity in crude muscle extract was about one-tenth those of spleen and lung. The activity per wet tissue weight was in roughly the same order except for a lower activity per wet weight of brain. 2. Upon chromatography of each crude extract on a Sephadex G-100 column, one major activity peak was eluted at a position corresponding to a molecular weight of about 41,000. This enzyme activity is attributed to cathepsin D [EC 3.4.23.5]. In addition, a minor activity peak was eluted in the case of spleen, lung and kidney at the break-through position, corresponding to a molecular weight of more than 100,000. This activity peak is presumably due to cathepsin E. These acid protease activities were, in most cases, strongly inhibited by pepstatin, an acid protease-specific peptide inhibitor. 3. The distribution of acid protease activity was investigated in the brain of crab-eating monkey (Macaca fascicularis). The activity was fairly evenly distributed among several regions of the brain, and its distribution was similar to those of other acid hydrolases, especially N-acetyl-beta-D-glucosaminidase [EC 3.2.1.30] and acid phosphatase [EC 3.1.3.2], which are marker enzymes of lysosomes.
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PMID:The structure and function of acid proteases. VII. Distribution and some properties of acid proteases in monkey tissues. 1 47

The specific enzymic properties, membrane or particle binding capacities, and the total activities of certain acid hydrolases, including cathepsin D, acid phosphatase, arylsulfatase, and five acid glycosidases have been compared in normal canine antral and fundic mucosae and in liver. The two major regions of the gastric mucosa, whose cell populations are comparable in type but have very distinct functions, also differ in many properties of their lysosomal enzymes. These differences necessitate several major modification in their method of assay. Using optimal conditions, the activities of most of these enzymes were found to differ: levels in the antrum, in spite of its high water and mucin-glycoprotein content, were significantly greater, suggesting that the high lysosomal hydrolytic activity may be associated with the rapid autophagic processes of normal turnover of its surface epithelial and mucous neck cells. Lysosomal membrane stability or latency is also greater in the antrum; this may account, in part at least, for antral resistance to erosions brought about by stress.
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PMID:Acid hydrolases. Assay of activity and latency in the varied mixed cell populations of canine gastric mucosa. 1 64

The partial purification of two intracellular proteinases from the protozoan parasite Entamoeba histolytica is reported. One of these enzymes is an acid proteinase exhibiting maximum activity at pH 3.5 (hemoglobin substrate), is little affected by a range of inhibitors or activators, and is presumed to be similar to cathepsin D. Also present is a neutral proteinase exhibiting optimum activity at pH 6.0 (azocasein) but only poorly hydrolyzing either hemoglobin or serum albumen. This latter enzyme displayed no metal ion requirement, but was markedly inhibited by thiol-blocking agents and activated by free sulhydryl-containing compounds.
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PMID:Partial purification and some properties of a neutral sulfhydryl and an acid proteinase from Entamoeba histolytica. 1 91

Cathepsin D, a potent acid proteinase, has been implicated in the pathogenesis of circulatory shock. The infusion of purified preparations of cathepsin D into intact animals resulted in significant depressions in core body temperature but failed to reproduce the cardiovascular disturbances seen in shock states.
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PMID:The effects of purified cathepsin D infusions in intact animals. 1 42

The presence of an acid proteinase with a high activity has been demonstrated in isolated odontoblast-predentine material from dentinogenically active rat incisors. The enzyme was identified as cathepsin D (EC 3.4.23.5). The possible significance of the enzymatic degradation of proteoglycans and glycosaminoglycans in the course of the calcification process is discussed.
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PMID:Cathepsin D activity in isolated odontoblasts. 1 34


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