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

The in vitro induction of lysosomal enzymes by phagocytosis was demonstrated in cultivated mouse peritoneal macrophages. The contribution of each of several steps in the endocytic process to enzyme induction was examined. The enzymatic response after the uptake of equal numbers of erythrocytes (RBC) and nondigestible particles were compared. Phagocytosis of RBC produced a marked increase in the levels of acid phosphatase, beta-glucuronidase, and cathepsin D. Puromycin (1 microg/ml) inhibited the enzyme response. In contrast, phagocytosis of polyvinyl toluene, polystyrene, and insoluble starch particles produced no increase in macrophage lysosomal enzymes, although fusion of phagosomes with preexisting lysosomes occurred normally. The endocytic stimulus to synthesis of inducible lysosomal enzymes, therefore, occurred at or beyond the stage of digestion. Purified protein (bovine gamma globulin) aggregates and homopolymer coacervates of poly-l-glutamic acid: poly-l-lysine were effective inducers of lysosomal acid phosphatase, beta-glucuronidase, and cathepsin D, whereas homopolymers of the same D-amino acids were ineffective as inducers. Both the quantity of phagocytized substrate and its rate of enzymatic hydrolysis appear to control the level and persistance of lysosomal hydrolases.
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PMID:In vitro induction of lysosomal enzymes by phagocytosis. 491 52

The human leucocyte migration in the leucocyte migration under agarose technique ( LMAT ) was investigated with specific inhibitors of aspartic, sulphhydryl , metallo- and serine proteinases. The general aspartic proteinase inhibitor pepstatin and the highly specific competitive cathepsin D inhibitor, N-gly-glu-gly-phe-leu-gly-D-phe-leu suppressed leucocyte migration at concentrations of 20-200 mumol/l and 30-59 mumol/l, respectively. The suphhydryl enzyme inactivator, N-ethylmaleimide suppressed leucocyte migration at concentrations of 100-200 mumol/l. Several inhibitors of serine- and metallo enzymes were tested, but none had any effect on leucocyte mobility, although the metal binding agent 8-hydroxyquinoline was strongly inhibitory to cell migration, the significance of which is discussed.
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PMID:Leucocyte migration inhibition in vitro with inhibitors of aspartic and sulphhydryl proteinases. 620 30

Plasmodium requires a living cell for growth and reproduction. Intraerythrocytically the parasite stores no reserve carbohydrate, relying entirely on host-supplied glucose and certain amino acids (glutamic acid) for its energy. Plasmodia are microaerophiles degrading glucose primarily to lactate rather than to CO2. The limited amounts of oxygen utilized may serve for biosynthetic purposes (e.g. pyrimidine biosynthesis) rather than being involved in an energy-yielding electron transport chain. Evidence for a parasite pentose pathway is weak since glucose-6-phosphate dehydrogenase has rarely been found; paradoxically, activity for 6-phosphogluconate dehydrogenase, the next enzyme in the pathway, is consistently identified. The parasites synthesize pyrimidines de novo, but being incapable of de novo purine biosynthesis they require preformed purines. Exogenously supplied purine, notably hypoxanthine derived from catabolism of erythrocytic ATP, is taken up and incorporated whereas pyrimidines are not. The capacity for de novo amino acid biosynthesis is limited and presumably haemoglobin supplies most of the amino acids required by the parasite. Degradation of haemoglobin, involving parasite proteases, notably a cathepsin D-like enzyme, leaves a characteristic golden-brown residue, haemozoin. Haemozoin consists of dimers of ferriprotoporphyrin IX, methaemoglobin and plasmodial proteins. For some species, isoleucine and methionine must be supplied exogenously for good plasmodial growth. Infected erythrocytes characteristically show altered permeability properties, changes which in large part contribute to parasite growth while at the same time impairing red cell function.
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PMID:Metabolism and surface transport of parasitized erythrocytes in malaria. 655 Dec 36

The content of 5 lysosomal hydrolases was examined in the rat liver and blood serum after compression of hind limb soft tissues in the presence of a long-term intake of excess doses of pyridoxine, riboflavin and glutamic acid. It was shown that the 14-day application of the drug complexes dramatically increased the overall content of cathepsin C, arylsulfatases A and B, beta-glucuronidase and p-acetyl-beta-D-galactosaminidase and reduced the overall content of cathepsin D in the rat liver. The non-sedimented content of the enzymes did not practically differ from the control magnitudes. In the blood serum, the content of cathepsin C and B1 approximated that seen in the control, while that of arylsulfatases A and B and p-acetyl-beta-D-galactosaminidase decreased, whereas the beta-glucuronidase content was 75% higher as compared to the basic characteristics. In the presence of administering the drug complexes, severe mechanical injury entailed the lowering of the content of the majority of rat liver lysosomal hydrolases. Besides, one could observe an essential fall of the non-sedimented content of cathepsin C and arylsulfatases A and B. The blood serum demonstrated an appreciable decrease in the content of cathepsins C and B1, p-acetyl-beta-D-galactosaminidase and arylsulfatases A and B. Thus, the fall of the non-sedimented content and diminished release of lysosomal hydrolases into the systemic circulation attest to the preservation of the structural and functional integrity of the liver cell lysosomal system during severe mechanical injury in the presence of combined excess intake of pyridoxine, riboflavin and glutamic acid.
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PMID:[Effect of pyridoxine, riboflavin and glutamic acid on lysosomal hydrolase activity in the liver and serum of rats during traumatic stress]. 715 Jul 36