Antibodies and Autoantibodies of Glycogen Phosphorylase b: Inactivation of Pig and Rabbit Enzymes

Abstract

Pig skeletal muscle glycogen phosphorylase b was purified using ammonium sulfate fractionation, DEAE-Sephadex A-50 and Sephadex G-200 column chromatography. The purified enzyme was used to immunize rabbits in the presence or in the absence of complete Freund adjuvant.Antibodies against pig phosphorylase in pure form were isolated from rabbit antisera using insoluble immunoadsorbents of pig phosphorylase. Autoantibodies against the rabbit enzyme were obtained from the same antisera using insoluble immunoadsorbents of rabbit phosphorylase. Complete inactivation of pig phosphorylase was accomplished by an antibody/enzynie molar ratio equal to 4 and autoantibody/enzyme molar ratio equal to 130. Complete inactivation of rabbit phosphorylase was accomplished by an antibody/enzyme molar ratio equal to 250 and autoantibody/enzyme molar ratio equal to 160. Passive haemagglutination technique gave positive results with minimum amounts of 0.02 pg/ml and 0.8 pg/ml for pig and rabbit phosphorylase respectively.Kinetic experiments have shown that antibodies and autoantibodies act as noncompetitive inhibitors of both enzymes with respect to AMP and glucose l-phosphate but exhibit a mixed type of inhibition with respect to glycogen. When glycogen hydrolysates were used as substrate in place of intact glycogen molecules a pronounced decrease in the inhibitory capacity of antienzyme on the enzyme was demonstrated.

Purification of Glycogen Phosphorylase from Bovine Brain and Immunocytochemical Examination of Rat Glial Primary Cultures Using Monoclonal Antibodies Raised Against This Enzyme

“…Presently it is not known whether this is true only for brain neurons in culture or also applies to neurons in situ. However, preliminary studies on brain slices indicate that phosphorylase activity resides predominantly within astrocytes and rarely, if at all, activity of our preparation (22-26 U/mg protein) is similar to previously published values for the purified muscle isozymc (Bergmeyer, 1968;Tzartos and Evangelopoulos, 1977;Butler et al, 1984), when assayed in the direction of glycogen hydrolysis. within neurons (K. Elmer, P. H. Reinhart, B. Hamprecht, W. Roggendorf and J. PeiKer, unpublished data).…”