Abstract
α‐1,4‐Glucan phosphorylase (EC 2.4.1.1) from the red seaweed Gracilaria sordida(Harv.) W. Nelson was adsorbed onto starch‐Sepharose 6B and Sephacryl S‐300 under specified conditions. The algal enzyme was purified to homogeneity by these two steps. A molecular weight of 97.4 kDa was observed on SDS‐polyacrylamide gel electrophoresis under reducing conditions, while the native molecular weight was 240 kDa asrevealed by 8‐25% native gradient gel electrophoresis or 245 kDa by gel filtration. The pI of the enzyme was 5.4. It had a Km of 227, 264, 285, and 453 μg ml‐1, respectively, towards glycogen, amylopectin, amylose, and maltodextrin. The enzyme activity was inhibited by cyclohexaamylose, ADP‐glucose, and UDP‐glucose. In contrast to other plant sources, cell‐free extracts of G. sordida contained only one form of phosphorylase.