In:
Lipids, Wiley, Vol. 35, No. 4 ( 2000-04), p. 365-371
Abstract:
Fatty acid α‐hydroxylase from Sphingomonas paucimobilis is an unusual cytochrome P450 enzyme that hydroxylates the α‐carbon of fatty acids in the presence of H 2 O 2 . Herein, we describe our investigation concerning the utilization of various substrates and the optical configuration of the α‐hydroxyl product using a recombinant form of this enzyme. This enzyme can metabolize saturated fatty acids with carbon chain lengths of more than 10. The K m value for pentadecanoic acid (C 15 ) was the smallest among the saturated fatty acids tested (C 10 –C 18 ) and that for myristic acid (C 14 ) showed similar enzyme kinetics to those seen for C 15 . As shorter or longer carbon chain lengths were used, K m values increased. The turnover numbers for fatty acids with carbon chain lengths of more than 11 were of the same order of magnitude (10 3 min −1 ), but the turnover number for undecanoic acid (C 11 ) was less. Dicarboxylic fatty acids and methyl myristate were not metabolized, but monomethyl hexadecanedioate and ω‐hydroxypalmitic acid were metabolized, though with lower turnover values. Arachidonic acid was a good substrate, comparable to C 14 or C 15 . The metabolite of arachidonic acid was only α‐hydroxyarachidonic acid. Alkanes, fatty alcohols, and fatty aldehydes were not utilized as substrates. Analysis of the optical configurations of the α‐hydroxylated products demonstrated that the products were S ‐enantiomers (more than 98% enantiomerically pure). These results suggested that this P450 enzyme is strictly responsible for fatty acids and catalyzes highly stereo‐ and regioselective hydroxylation, where structure of ω‐carbon and carboxyl carbon as well as carbon chain length of fatty acids are important for substrate‐enzyme interaction.
Type of Medium:
Online Resource
ISSN:
0024-4201
,
1558-9307
DOI:
10.1007/s11745-000-533-y
Language:
English
Publisher:
Wiley
Publication Date:
2000
detail.hit.zdb_id:
2030265-4
SSG:
12
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