Control of Acetohydroxy Acid Synthetase in Neurospora crassa
- 1 November 1972
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Biochemistry
- Vol. 72 (5) , 1139-1145
- https://doi.org/10.1093/oxfordjournals.jbchem.a130001
Abstract
Acetohydroxy acid synthetase of Neurospora crassa was found to be inhibited by L-valine and to a lesser degree by L-isoleucine, when mitochondrial pellet suspension was used for the assay of this enzyme. When acetohydroxy acid synthetase was extracted from mitochondria by various chemical and physical means, its sensitivity to valine was greatly reduced. The inhibition of the enzyme activity by valine was reversed by ATP or ADP. The enzyme was also activated by ATP, ADP, and inorganic orthophosphate. The supernatant prepared by sonic disruption and centrifugation at 215,000×g contained acetohydroxy acid synthetase which had a broad pH optimum between 8 and 9, and was not affected by valine, ATP, and ADP. Based on the above results the regulation of acetohydroxy acid synthetase activity was discussed.Keywords
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