Biotransformation of crotonobetaine to L(-)-carnitine in Proteus sp.

Engemann, C Elssner, T Kleber, HP

C. Engemann et al., Biotransformation of crotonobetaine to L(-)-carnitine in Proteus sp., ARCH MICROB, 175(5), 2001, pp. 353-359

24

INGLESE

Article

Microbiology

ARCHIVES OF MICROBIOLOGY

0302-8933 → ACNP

175

5

2001

353 - 359

ISI

0302-8933(200105)175:5<353:BOCTLI>2.0.ZU;2-Q

Two proteins, component I (CI) and component II (CII), catalyze the biotran sformation of crotonobetaine to L(-)-carnitine in Proteus sp. CI was purifi ed to electrophoretic homogeneity from cell-free extracts of Proteus sp. Th e N-terminal amino acid sequence of CI showed high similarity (80%) to the caiB gene product from Escherichia coli O44K74, which encodes the L(-)carni tine dehydratase. CI alone was unable to convert crotonobetaine into L(-)-c arnitine even in the presence of the cosubstrates crotonobetainyl-CoA or ga mma -butyrobetainyl-CoA, which are essential for this biotransformation. Th e relative molecular mass of CI was determined to be 91.1 kDa. CI is compos ed of two identical subunits of molecular mass 43.6 kDa. The isoelectric po int is 5.0. CII was purified to electrophoretic homogeneity from cell-free extracts of Proteus sp, and its N-terminal amino acid sequence showed high similarity (75%) to the caiD gene product of E. coli O44K74. The relative m olecular mass of CII was shown to be 88.0 kDa, and CII is composed of three identical subunits of molecular mass 30.1 kDa. The isoelectric point of CI I is 4.9. For the biotransformation of crotonobetaine to L(-)-carnitine, th e presence of CI, CII, and a cosubstrate (crotonobetainyl-CoA or gamma -but yrobetainyl-CoA) were shown to be essential.