title: Limited proteolysis of D-beta-hydroxybutyrate dehydrogenase: relationships between phospholipid-protein interactions and catalytical activity.
abstract: 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.
mesh_terms: D000818:Animals; D005260:Female; D006884:Hydroxybutyrate Dehydrogenase / Q000378:metabolism*; D007700:Kinetics; D008930:Mitochondria, Liver / Q000201:enzymology; D008970:Molecular Weight; D010446:Peptide Fragments / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D011247:Pregnancy; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D013367:Submitochondrial Particles / Q000201:enzymology
chemical_list: D010446:Peptide Fragments; D010743:Phospholipids; D011480:Protease Inhibitors; D006884:Hydroxybutyrate Dehydrogenase; D010447:Peptide Hydrolases