1) NADH-cytochrome c reductase activity in membrane was inhibited by p-chlo romercuric benzoate and N-ethylmaleimide, but not by KCN, NaN
3, Antimycin A or rotenone.
2) Both NADH-cytochrome c reductase and NADH-ferricyanide dehydrogenase located in the membrane and microsome showed the same Km value respectively. These Km values were retained unchanged even in case of CCl
4 treatment
in vivo.
3) Membrane also contained cytochrome b
5 and P-450, of which contents were much lower than those in microsome. CCl
4, however, resulted in an increase of these heme proteins to twice in membrane, but a decrease to half in microsome.
4) NADH-cytochrome b
5 reductase activity was only one third of NADH-cytochrome c reductase activity in membrane irrespective of CCl
4 administration
in vivo.
5) It is proposed that NADH-cytochrome c reductase in membrane orignates from microsome, but not from mitochondria, and that increase of enzyme activity after CCl
4 administration may be caused by migration of heme- and flavo-proteins from endoplasmic reticulum to plasma membranes of liver cells
in vivo.
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