D. Meesapyodsuk et al., Probing the mechanism of a cyanobacterial Delta 9 fatty acid desaturase from Spirulina platensis C1 (Arthrospira sp PCC 9438), COMP BIOC B, 129(4), 2001, pp. 831-835
Citations number
16
Categorie Soggetti
Biochemistry & Biophysics
Journal title
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY
The initial and rate determining step in the mechanism of fatty acid desatu
rases has been proposed to be breakage of one of the C-H bonds at the site
of the incipient double bond. This has been investigated and supported for
a number of eukaryotic fatty acid desaturases through the use of kinetic is
otope effect experiments with deuterated substrates, In order to probe the
reaction catalyzed by the cyanobacterial Delta9 desaturase and compare it t
o the eukaryotic desaturases, the desC gene of Spirulina platensis, strain
C1 (Arthrospira sp. PCC 9438) was expressed in a desaturase mutant of baker
's yeast. Kinetic isotope effects were performed by culturing yeast transfo
rmants with deuterated thia-substituted stearic acids. A large kinetic isot
ope effect was found for the 9 position, in qualitative agreement with resu
lts from eukaryotic desaturases. (C) 2001 Elsevier Science Inc. All rights
reserved.