Tyrosine and Phenylalanine Ammonia Lyase Activities during Shoot Initiation in Tobacco Callus Cultures

Both phenylalanine ammonia lyase and tyrosine ammonia lyase were detected in tobacco (Nicotiana tabacum L. Wisconsin 38) callus. The enzymes were separated from each other by Sephadex G-200 column chromatography. Increased activity of tyrosine ammonia lyase was observed during culture of tobacco callus under shoot-forming conditions, while activity of phenylalanine ammonia lyase increased during culture under non-organ-forming conditions. Confirmation of these findings was obtained by examining the incorporation of [(14)C]tyrosine and [(14)C]phenylalanine into p-coumarate and trans-cinnamate, respectively.