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Study of the Δ12‐desaturase system of Lipomyces starkeyi
Author(s) -
Lomascolo Anne,
Dubreucq Eric,
Galzy Pierre
Publication year - 1996
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/bf02529871
Subject(s) - oleic acid , chemistry , linoleic acid , microsome , fatty acid desaturase , biochemistry , enzyme , clinical chemistry , fatty acid , lipidology , centrifugation , polyunsaturated fatty acid
Abstract The specific activity of the microsomal Δ12‐desaturase system, which transforms oleic acid into linoleic acid, was about 16 pmol/min/mg protein. However, most of the total activity was nonsedimentable even after a 2× g centrifugation for 100 min. The study of various physicochemical parameters showed that this enzymatic complex, functioning optimally between pH 7 and 8, had low thermal stability. Ca 2+ , which may cause an aggregation of the microsomes, and Hg 2+ completely inhibited the activity, whereas Mg 2+ , Mn 2+ , and Zn 2+ were activators. The Δ12‐desaturase system was relatively specific toward oleic acid, though isomers of this fatty acid also had an action, either as substrates or as competitive inhibitors, on the activity of the system. The study of the effect of the exogenous oleoyl‐CoA and elaidoyl‐CoA on the specific activity of the Δ12‐desaturase system showed a preference toward oleoyl‐CoA.