TAXONOMIC DISTRIBUTION OF AMMONIA-LYASES FORL-PHENYLALANINE ANDL-TYROSINE IN RELATION TO LIGNIFICATION

Abstract

A general survey of the plant kingdom and a number of bacterial and animal sources has been made for the enzymes L-phenylalanine ammonia-lyase (EC. 4.1.3.5.) and L-tyrosine ammonia-lyase (EC. 4.1.3.). The above enzymes could not be detected in bacteria, animal tissues, algae, lichens, fungi, or mosses, substantiating the view that their presence may be correlated with the ability of plants to synthesize phenylpropanoid compounds related to lignin. Cereals had the highest content of tyrosine ammonia-lyase, as expected from their known high efficiency in converting tyrosine to lignin. In addition, Chrysanthemum sp. (in which neither enzyme could be detected) has been shown to contain potent, natural inhibitors of these enzymes.