COORDINATED REGULATION OF 4-COUMARATE-COA LIGASE AND PHENYLALANINE AMMONIA-LYASE MESSENGER-RNAS IN CULTURED PLANT-CELLS

Abstract

4-Coumarate:CoA ligase (EC 6.2.1.12) from cell suspension cultures of parsley (Petroselinum hortense) was extensively purified. The enzyme behaved as a monomer with a MW of .apprx. 60,000. A rabbit antiserum to the purified enzyme was obtained and used to determine the rates of 4-coumarate:CoA ligase synthesis under various conditions of induction, such as a short-term or continuous irradiation and treatment of the cells with an elicitor preparation from a fungal pathogen [Phytophthora megasperma f. sp. sojae]. In all cases, the time course of changes in the rate of synthesis, measured both in vivo and in vitro, was very similar for 4-coumarate:CoA ligase and a closely related enzyme phenylalanine ammonia-lyase (EC 4.3.1.5). Apparently, the mRNA activities encoding the 2 enzymes are regulated in a coordinated manner.