EFFECT OF SULFATED POLYSACCHARIDES AND SULFATE ANIONS ON THE AMP-DEPENDENT ACTIVITY OF PHOSPHORYLASE-B

The effect of sulfated polysaccharides on the AMP-dependent activity of rabbit muscle phosphorylase b as compared with that of Na2SO4 has been studied. It has been shown that sulfated polysaccharides and Na2SO4 greatly stimulated AMP-activation of the enzyme at low AMP concentrations. Dextran sulfate and Na2SO4 desensitized the allosteric interactions of the enzyme towards the nucleotide activator and reversed the enzyme inhibition caused by glucose-6-phosphate and glucose. Furthermore, it was found that while dextran sulfate decreased the Km value for both substrates, glucose-1-phosphate and glycogen, sulfate anions decreased only the Km value for glycogen. © 1979.