GLUCOSE-INDUCED INACTIVATION OF ISOCITRATE LYASE IN SACCHAROMYCES-CEREVISIAE IS MEDIATED BY AN INTERNAL DECAPEPTIDE SEQUENCE

In this work we have investigated the role of specific peptide sequenc es for glucose-inactivation of the yeast isocitrate lyase, Thus, diffe rent fragments of the ICL1 coding region were fused to the lacZ gene o f E, coli to provide a reporter construction, Determinations of beta-g alactosidase activities indicated that the decapeptide sequence KTKRNY SARD, located between amino acid residues 37 and 46 of isocitrate lyas e, is important for glucose induced proteolytic inactivation, Further experimental evidence was provided by insertion of this sequence into a glucokinase-beta-galactosidase fusion protein, which is not sensitiv e to glucose regulation, The decapeptide inserted conferred glucose in activation to this construct, confirming that it is both necessary and sufficient as a signal.