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Modification of microsomal lipid composition and electron transport enzyme activities in isovalerate‐supplemented cells of novel Tetrahymena ISO
Author(s) -
Watanabe Takehito,
Fukushima Hirofumi,
Sasaki Noboru,
Umeki Shigenobu,
Suezawa Yoshie,
Nozawa Yoshinori
Publication year - 1983
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02535428
Subject(s) - isovalerate , reductase , microsome , biochemistry , cytochrome , phospholipid , tetrahymena , enzyme , biology , chemistry , membrane , butyrate , fermentation
Tetrahymena ISO cells, which have an unusually high level of iso odd‐numbered fatty acids, were grown medium supplemented with various concentrations of isovalerate. There was a marked increase in the total proportion of iso odd‐numbered fatty acids in supplemented whole cells (28.9→70.3%) and microsomes (37.7→84%), with a corresponding decrease in normal fatty acids, although no significant alteration of phospholipid composition was observe during 11 hr isovalerate‐supplementation. Microsomal palmitoyl‐CoA and stearoyl‐CoA desaturase activities in isovalerate‐supplemented cells decreased by 45.7% and 30.6% during 11 hr, respectively. NADH‐cytochrome c reductase and NADH‐ferricyanide reductase activities as well as the content of cytochrome b 560ms , which is similar to mammalian microsomal cytochrome b 5 , were reduced in microsomes from 11 hr‐supplemented cells, whereas NADPH‐cytochrome c reductase activity was constant. It is suggested that the alteration of the cross‐sectional area of lipid molecules in the bilayer, which results from the replacement of normal fatty acids with iso ‐15∶0 and iso ‐17∶1, would result in the decline of palmitoyl‐ and stearoyl‐CoA desaturation in the isovalerate‐supplemented cells, in order to maintain membrane fluidity at a functional level.