Citramalate synthase yields a biosynthetic pathway for isoleucine and straight- and branched-chain ester formation in ripening apple fruit.

ABSTRACT: A plant pathway that initiates with the formation of citramalate from pyruvate and acetyl-CoA by citramalate synthase (CMS) is shown to contribute to the synthesis of α-ketoacids and important odor-active esters in apple (Malus × domestica) fruit. Microarray screening led to the discovery of a gene with high amino acid similarity to 2-isopropylmalate synthase (IPMS). However, functional analysis of recombinant protein revealed its substrate preference differed substantially from IPMS and was more typical of CMS. MdCMS also lacked the regulatory region present in MdIPMS and was not sensitive to feedback inhibition. ¹³C-acetate feeding of apple tissue labeled citramalate and α-ketoacids in a manner consistent with the presence of the citramalate pathway, label

SUBMITTER: Sugimoto N 

PROVIDER: S-EPMC7826400 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature