(1) a 2-[(omega-methylsulfanyl)alkyl]malate = a 2-[(omega-methylsulfanyl)alkyl]maleate + H2O;
(2) a 3-[(omega-methylsulfanyl)alkyl]malate = a 2-[(omega-methylsulfanyl)alkyl]maleate + H2O
The enzyme, characterized from the plant Arabidopsis thaliana, is involved in the L-methionine side-chain elongation pathway, forming substrates for the biosynthesis of aliphatic glucosinolates. By catalysing a dehydration of a 2-[(omega-methylsulfanyl)alkyl]maleate, followed by a hydration at a different position, the enzyme achieves the isomerization of its substrates. The enzyme is a heterodimer comprising a large and a small subunits. The large subunit can also bind to an alternative small subunit, forming EC 4.2.1.33, 3-isopropylmalate dehydratase, which participates in L-leucine biosynthesis.
Knill T, Reichelt M, Paetz C, Gershenzon J, Binder S
Title
Arabidopsis thaliana encodes a bacterial-type heterodimeric isopropylmalate isomerase involved in both Leu biosynthesis and the Met chain elongation pathway of glucosinolate formation.
