Open AccessAcetyl‐CoA Hydrolase; Activity, Regulation and Physiological, Significance of the Enzyme in Brown Adipose Tissue from Hamster
Author(s) -
BERNSON Vibeke S. M.
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10705.x
Subject(s) - hydrolase , hamster , adipose tissue , enzyme , brown adipose tissue , enzyme assay , chemistry , biochemistry , biology , endocrinology
1 Acetate production in hamster brown adipose tissue is a consequence of the existence of an acetyl‐CoA hydrolase. The enzyme is soluble and is localised to the mitochondrial matrix. 2 Acetyl‐CoA hydrolase has an apparent K m for acetyl‐CoA of 51 μM, and a specific activity at 30 °C of 870 nmol of acetate formed/min per mg 1 × g supernatant protein. 3 The enzyme is noncompetitively activated by ADP and inhibited by NADH and the effect of these nucleotides may well serve to regulate the enzyme activity in vivo. 4 A strong product inhibition by CoA is observed. The inhibition is of S‐linear‐I‐hyperbolic noncompetitive nature. 5 The hydrolase has a Q 10 of 2.0, which represents a 7.3% change in the rate of acetate production per °C. The energy of activation is 12200 cal/mol (53 905 J/mol). 6 The regulatory role of acetyl‐CoA hydrolase for fatty acid oxidation in brown adipose tissue of the hamster (a hibernator) at low as well as at normal body temperature is discussed.