Yeast isopropylmalate isomerase

Yeast isopropylmalate isomerase of the leucine biosynthetic pathway, which catalyzes a totally analogous reaction to that of aconitase, converts 3-hydroxy-3-carboxy-4-methylpentanoate to 2-hydroxy-3-carboxy-4-methylpentanoate via an allylic intermediate. In its initial characterization by EPR spectroscopy, a high-field shift in its EPR signal from a g-average of 1.96 to 1.90 is seen upon addition of substrate (70). This result suggests that its mechanism is the same as that found for aconitase. 

Emptage, M. H. Yeast isopropylmalate isomerase as an iron sulfur protein. In Biosynthesis of Branched Chain Amino Acids, Proc. Workshop Barak, Z. E., Chipman, D. M. and Schloss, J. V., Ed. VCH, 1988, pp 315-328. 

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