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 effect of insulin on the concentration of different glycosaminoglycan (CG) fractions was different in different segments of aorta. Chondroitin sulphate A and heparin were increased in the aortic arch, thoracic and abdominal aorta, while chondroitin sulphate B and C were increased only in the aortic arch and abdominal aorta. Heparin sulphate and hyalutonic acid were increased only in the abdominal aorta. In the liver, significant increases occurred in all GG fractions. All enzymes studied which are involved in the biosynthesis of GG precursors, i.e. glucosaminphosphate isomerase, UDP glucose dehydrogenase and glucose-1-phosphate uridylyltransferase, were increased in the animals of the insulin group, while all enzymes involved in the degradation of GG, i.e. hyalurono glucosidase, beta-glucosaminidase, arylsulphatase, and cathepsin D, were decreased. Concentration of hepatic PAPS, activity of the sulphate-activiting system and sulphotransferase increased on administration of insulin.
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PMID:Insulin and metabolism of glycosaminoglycans in rabbits. 71 66

We attempted to establish within which organelle UDP-Glc:ceramide beta 1----1'glucosyltransferase (GlcT) is located and moreover to obtain information about its orientation on intracellular membranes as well as that of UDP-Gal:glucosylceramide beta 1----4galactosyltransferase (GalT-2) and CMP-NeuAc:lactosylceramide alpha 2----3sialyltransferase (SAT-1). An extremely purified Golgi apparatus fraction was the only liver fraction where a ceramide-dependent formation of glucosylceramide could be demonstrated. This Golgi fraction, mainly constituted by stacks of intact cisternae which retained the same topographical orientation as in vivo, was then incubated with liposomal dispersions of glycosphingolipid-glycosyltransferase acceptors in reaction mixtures containing all the requirements for enzyme activity but no detergent. Under such conditions, SAT-1 and other late acting glycosyltransferases were over 90% latent, while both GlcT and GalT-2 were just as active as in the detergent-containing assay; they were still inhibited by EDTA. Sepharose-immobilized ceramide and Sepharose-immobilized glucosylceramide were found to be suitable acceptors for GlcT and GalT-2, respectively, still using intact Golgi cisternae as the enzyme source. Moreover, a part of GlcT and GalT-2 activity was released from intact Golgi cisternae upon cathepsin D treatment. These results provide strong evidence that GlcT and GalT-2 face the cytoplasmic side of the Golgi apparatus, whereas SAT-1 and the other late acting enzymes face the luminal side.
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PMID:Topography of glycosyltransferases involved in the initial glycosylations of gangliosides. 183 52

The kinetic properties of UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) purified to homogeneity from lactating bovine mammary gland have been investigated. GlcNAc-phosphotransferase transferred GlcNAc 1-phosphate from UDP-GlcNAc to the synthetic acceptor alpha-methylmannoside, generating GlcNAc-1-phospho-6-mannose alpha-methyl, the structure of which was confirmed by mass spectroscopy. GlcNAc-phosphotransferase was active between pH 5.7 and 9.3, with optimal activity between pH 6.6 and 7.5. Activity was strictly dependent on Mg2+ or Mn2+. The Km for Mn2+ was 185 microM. The Km for UDP-GlcNAc was 30 microM, and that for alpha-methylmannoside was 63 mM. The enzyme was competitively inhibited by UDP-Glc, with a Ki of 733 microM. The 166-kDa subunit was identified as the catalytic subunit by photoaffinity labeling with azido-[beta-32P]UDP-Glc. Purified GlcNAc-phosphotransferase utilizes the lysosomal enzyme uteroferrin approximately 163-fold more effectively than the non-lysosomal glycoprotein ribonuclease B. Antibodies to GlcNAc-phosphotransferase blocked the transfer to cathepsin D, but not to alpha-methylmannoside, suggesting that protein-protein interactions are required for the efficient utilization of glycoprotein acceptors. These results indicate that the purified bovine GlcNAc-phosphotransferase retains the specificity for lysosomal enzymes as acceptors previously observed with crude preparations.
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PMID:Bovine UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase. II. Enzymatic characterization and identification of the catalytic subunit. 894 Jan 56