Characterization of intestinal gamma-glucoamylase deficiency in CBA/Ca mice
Quezada-Calvillo, R.; Senchyna, M.; Underdown, B.J.
American Journal of Physiology 265(6 Pt 1): G1150-G1157
1993
ISSN/ISBN: 0002-9513 PMID: 8279566 Document Number: 406331
In previous work, we found that CBA/Ca mice display only 20% of the maltase activity present in other mouse strains. In this study, we characterized more fully the maltase deficiency in CBA/Ca mice. Virtually all of the intestinal maltase activity of CBA/Ca mice was inactivated at 50 degrees C, indicating that it was due only to the sucrase-isomaltase complex. High-performance liquid chromatographic analysis revealed that CBA/Ca mice had undetectable maltase activity displaying the molecular mass characteristic of murine gamma-glucoamylase (gamma-GA) (530 kDa). Gel electrophoretic analysis confirmed that CBA/Ca mice lacked maltase activity with molecular mass of 530 kDa corresponding to gamma-GA. Two-dimensional electrophoretic analysis revealed that the gamma-GA deficiency in CBA/Ca mice was due to the failure to synthesize the enzyme and not to the synthesis of an inactive protein. Gamma-GA maltase activity could not be induced in CBA/Ca mice by a diet rich in starch, whereas the activity of other disaccharidases were readily increased. Gamma-GA-deficient CBA/Ca mice appear to lack any gross metabolic abnormality resulting from this defect.