Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Different forms of D-beta-hydroxybutyrate dehydrogenase were submitted to various proteases in order to get information on enzyme molecular structure and on phospholipid -enzyme interaction. Except for leucinaminopeptidase, all proteases tested inactivated the phospholipid-free enzyme, while no inactivation was observed with the lecithin-enzyme complex. However, non-reactivating phospholipid gave very poor protection against proteases. After endopeptidase treatment, a new band of 25,000 Mr appeared instead of the 32,000 Mr band (apodehydrogenase). Surprisingly, the so-called protected form of the enzyme (lecithin-complex) was also proteolysed while still enzymatically active. Carboxypeptidase A inactivated quite thoroughly the enzyme although the 32,000 Mr band appeared unaffected. These results demonstrate that the configuration of the phospholipid-free apodehydrogenase is quite vulnerable to most proteases, in contrast to the configuration of the lecithin-complexed enzyme. The N-terminal end is probably blocked while the C-terminal end looks quite important for enzymatic activity.
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PMID:Limited proteolysis of D-beta-hydroxybutyrate dehydrogenase: relationships between phospholipid-protein interactions and catalytical activity. 638 1

Monoclonal antibodies (mAbs) have been used to study structure-function relationships of (R)-3-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30), a lipid-requiring mitochondrial membrane enzyme with an absolute and specific requirement for phosphatidylcholine (PC) for enzymic activity. The purified enzyme (apoBDH, devoid of phospholipid and thereby inactive) can be re-activated with preformed phospholipid vesicles containing PC or by short-chain soluble PC. Five of six mAbs cross-react with BDH from bovine heart and rat liver, including two mAbs to conformational epitopes. One mAb was found to be specific for the C-terminal sequence of BDH and served to: (1) map endopeptidase cleavage and epitope sites on BDH; and (2) demonstrate that the C-terminus is essential for the activity of BDH. Carboxypeptidase cleavage of only a few (< or = 14) C-terminal amino acids from apoBDH (as detected by the loss of C-terminal epitope for mAb 3-10A) prevents activation by either bilayer or soluble PC. Further, for BDH in bilayers containing PC, the C-terminus is protected from carboxy-peptidase cleavage, whereas in bilayers devoid of PC the C-terminus is cleaved, and subsequent activation by PC is precluded. We conclude that: (1) the C-terminus of BDH is essential for enzymic activity, consistent with the prediction, from primary sequence analysis, that the PC-binding site is in the C-terminal domain of BDH; and (2) the allosteric activation of BDH by PC in bilayers protects the C-terminus from carboxypeptidase cleavage, indicative of a PC-induced conformational change in the enzyme.
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PMID:Monoclonal antibodies for structure-function studies of (R)-3-hydroxybutyrate dehydrogenase, a lipid-dependent membrane-bound enzyme. 768 68