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)

Prolonged starvation in rats is accompanied by consistent increases in the total cardiac activity and the nonsedimentable activity of cathepsin D, the major detectable lysosomal acid proteinase in the heart. Fluorescent staining of rabbit hearts with specific anticathepsin D antiserum reveals that the increase occured predominantly in myocytes, but increased formation of autophagic vacuoles cannot be demonstrated in the myocardial cells by electron microscopy. No changes in cathepsin D occur in animals fed pure carbohydrate or pure fat diets for similar periods, indicating that it is caloric deficiency and not dietary protein deficiency that alters catheptic activity. At the same time that cardiac cathepsin D activity increases markedly, acid phosphatase increases slightly, and the activity of beta-acetyl-glucosaminidase is significantly lower than in hearts of fed rats. The data are compatible with the hypothesis that increased activity of lysosomal acid proteinase may contribute to the net protein catabolism and cardiac atrophy that accompany starvation, especially late in the period of food deprivation. A generalized activation of all lysosomal enzymes does not occur with starvation, however, and the activities of some lysosomal enzymes in the heart decrease.
 ...
PMID:Dietary control of cardiac lysosomal enzyme activities. 121 47

The role which two proteolytic enzymes (cathepsin D, CD and calcium-activated protease, CAP) might play in the early anabolic and subsequent catabolic phases of skeletal muscle protein metabolism was investigated in rats fed normal and protein-deficient (50 g/kg) diets. Enzyme measurements were performed on crude homogenate and subcellular fractions of mixed thigh muscle. In normal pregnancy there was no evidence that the changes in muscle protein mass which occurred were assisted by changes in the activities of CD or CAP. CAP activity was, however, reduced throughout protein-deficient pregnancy. Electron micrographs of gastrocnemius muscle samples taken on day 21 of pregnancy suggested increased lysosome numbers in the protein-deficient animals. However, the specific activity of CD in the muscle microsomal-mitochondrial fraction from these animals showed decreased specific activity. Thus, neither CD nor CAP play any major role in releasing amino acids from maternal skeletal muscle for placental and fetal use during protein deficiency. Changes in CAP activity in early pregnancy may indirectly help to protect the fetus from protein deficiency by allowing maternal protein mass to accumulate early in pregnancy for catabolism and use at a later stage.
 ...
PMID:Cathepsin D and calcium-activated protease activities in skeletal muscle of normal and protein-deficient pregnant rats. 631 33

Rat peritoneal macrophages contained high proteolytic activity that was significantly enhanced under the stress induced by protein deficiency. The aspartyl protease cathepsin D which has been known to be the most active protease in endocytic processes was extracted from the macrophages recovered from control (20% protein fed) and protein deficient (4% protein fed) rats and was affinity purified and characterized further. The cathepsin D from the control sample exhibited better recovery, purification and higher specific activity compared to that from the deficient groups. Apparently the pH optima and heat stability of the enzyme from both the groups were similar. The SDS PAGE profile clearly indicated the presence of greater amounts of active forms of cathepsin D in the deficient samples in vivo itself which reflected in a reduction in Km value of the enzyme. Subtle differences observed in the activity of these macrophage proteases in the protein deficient rats may be partly responsible for the enhanced degradation of macrophage membrane proteins reported earlier.
 ...
PMID:Activation of protease activity in rat peritoneal macrophages in protein deficiency: characterization of cathepsin D. 897 98