Tissue-specific forms of β-hydroxybutyrate dehydrogenase oxidize the D- or L-enantiomers of β-hydroxybutyrate in the terrestrial gastropodCepaea nemoralis

✍ Scribed by Stuart, J. A.; Ballantyne, J. S.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 70 KB
• Volume: 278
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/(sici)1097-010x(19970601)278:2<115::aid-jez7>3.0.co;2-s

✦ Synopsis

β-hydroxybutyrate dehydrogenase (BHBDH) catalyzes the interconversion of the ketone bodies acetoacetate (Acac) and D-b-hydroxybutyrate (BHB). In virtually all animals, including mammals and fish (Newsholme and Leech, '83) and freshwater molluscs (Meyer et al., '86), BHBDH exists within the mitochondria. The mammalian BHBDH is a popular model for the study of the kinetics of membrane-bound enzymes since it has an obligate requirement for certain phospholipid species (Isaacson et al., '79).

We have recently described a different and unique form of BHBDH found in the terrestrial snail Cepaea nemoralis (Stuart and Ballantyne, '96) which differs in two respects from the enzyme described above. This enzyme occurs in the cytosol of hepatopancreas cells and oxidizes exclusively the L-enantiomer of BHB. This form of BHBDH does not occur in all tissues of C. nemoralis. Here, we describe the presence in other tissues of another cytosolic form of BHBDH with an enantiomeric specificity for the D-stereoisomer and demonstrate that it is a separate protein from L-BHBDH.