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B6db references: 86295761

type Journal Article
authors Shanker, J.; Datta, K.
title Excess generation of endogenous heme inhibits L-alanine:4,5- dioxovalerate transaminase in rat liver mitochondria
journal Biochem Biophys Res Commun
ui 86295761
year (1986)
volume 138
number 2
pages 751-7.
keywords Animal
abstract In the present study, we examined the possibility that the excess heme generation within mitochondria may provide a local concentration, sufficient to inhibit the activity of L-alanine:4,5-dioxovalerate transaminase, the enzyme proposed for an alternate route of delta- aminolevulinic acid biosynthesis in mammalian system. This was accomplished by assaying together L-alanine:4,5-dioxovalerate transaminase and heme synthetase activities in intact mitochondria isolated from rat liver. Endogenous heme in intact mitochondria has been generated in excess, by increasing the concentration of the substrate of heme synthetase. Our studies showed that the activity of L- alanine:4,5-dioxovalerate transaminase decreased as the rate of heme formation increased. In intact mitochondria, almost 50% inhibition of alanine:4,5-dioxovalerate transaminase was obtained with 4.0 mumole of heme generation. We conclude that end product inhibition of L- alanine:4,5-dioxovalerate transaminase by hemin, which was proposed in earlier report by us (FEBS Letter (1985), 189, 129), is an important physiological mechanism for the regulation of hepatic heme biosynthesis.
last changed 2002/11/12 16:17

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