High sequence conservation between isocitrate lyase from Escherichia coli and Ricinus communis.

The deduced amino acid sequences of isocitrate lyase (EC 4.1.3.1) from Escherichia coli and Ricinus communis (castor bean) were compared and regions of high homology between the two enzymes were identified. The castor-bean enzyme had a 14 amino acid amino-terminal, and a 25 amino acid carboxy-terminal extension and a 102 amino acid central insertion compared to the E. coli enzyme. Enzymatic data were used to attempt to identify specific amino acids in the active site. Comparisons with putative peroxisomal/gloxysomal targeting sequences were made and a region including part of the central insertion of the castor bean enzyme was tentatively identified.