1. The specific activity of monoamine oxidase was found to be greater in liver mitochondria from ob/ob mice than from lean mice. The activities of marker enzymes were similar in both tissues. 2. Experiments with various substrates (5-hydroxytryptamine, benzylamine and tyramine) and inhibitors (clorgyline and deprenyl) indicated that, unlike rat liver mitochondria, mouse liver mitochondria contain a predominance of the B-form of monoamine oxidase. 3. The Km values for lean and ob/ob mice were the same for any given substrate and were in the increasing order 5-hydroxytryptamine less than tyramine less than benzylamine. Vmax. was approximately 50% greater in obese than in lean mice. 4. Extraction of liver mitochondria with acetone/water or acetone/water/NH3 to remove lipids decreased the enzyme activity relatively more in obese- than in lean-mice preparations, but residual activity was the same in both preparations.
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Research Article| March 01 1979
Liver monoamine oxidase in the obese–hyperglycaemic (ob/ob) mouse
M Limson-Zamora ;
Biochem J (1979) 177 (3): 943–949.
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J H Tong, M Limson-Zamora, A D'Iorio, N Bégin-Heick; Liver monoamine oxidase in the obese–hyperglycaemic (ob/ob) mouse. Biochem J 1 March 1979; 177 (3): 943–949. doi: https://doi.org/10.1042/bj1770943
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