L-PHENYLALANINE AMMONIA-LYASE - BINDING OF POLYSACCHARIDE BY THE ENZYME FROM MAIZE

The amount of carbohydrate associated with maize phenylalanine ammonia-lyase at all stages of purification was appreciable; monosaccharides present in hydrolyzed enzyme were arabinose, ribose, fucose, galactose, mannose, and glucose. The ratio of neutral sugars: amino sugars was 9 : 1. As much as 90% of the carbohydrate could be removed as a high molecular weight polysaccharide by gel electrophoresis, DEAE-Sephadex chromatography, or trichloracetic acid precipitation. Precipitation with (NH4)2SO4 and column chromatography on agarose or hydroxylapatite did not decrease the carbohydrate : protein ratio. Removal of the polysaccharide (composed of arabinose and galactose) is accompanied by large losses of activity. In vivo localization of the enzyme may depend on its ability to bind specific polysaccharides. © 1979.