Rodent and Human Acid &alpha-Glucosidase.

The lysosomal acid α-glucosidase has been purified more than 10000-fold from rat and mice liver and from human placenta. The kinetic properties of the human enzyme are similar to those previously described for the rodent enzyme, with the main exception of the absence of inhibition by an excess of maltose. Antibodies were obtained by injection of the pure rat liver, mouse liver or human placental α-glucosidase to rabbits. The property of the enzyme of hydrolysing glycogen or to catalyse transglucosylation from maltose to glycogen could be nearly completely inhibited by the antibodies whereas the hydrolysis of small molecular substrates was much less inhibited. Within the same species, the same amount of enzyme was inhibited by a given amount of antibodies, whatever the tissue used as a source of enzyme. A partial cross-reactivity was observed from species to species. The presence of an immunologically reacting protein in tissues from patients with type-II-glycogenosis could not be demonstrated either by double-diffusion test or by antibodies consumption. Similar negative results were also obtained with normal human liver in which acid α-glucosidase has been inactivated at alkaline pH. [ABSTRACT FROM AUTHOR]