Characterization of intestinal gamma-glucoamylase deficiency in CBA/Ca mice.
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.
Quezada-Calvillo
R
R
Department of Pathology, McMaster University, Hamilton, Ontario, Canada.
Senchyna
M
M
Underdown
B J
BJ
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004186:Disaccharidases / Q000096:biosynthesis / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction; D005087:Glucan 1,4-alpha-Glucosidase / Q000172:deficiency* / Q000378:metabolism; D007082:Ileum / Q000201:enzymology; D007413:Intestinal Mucosa / Q000201:enzymology*; D007583:Jejunum / Q000201:enzymology; D051379:Mice; D008808:Mice, Inbred CBA / Q000378:metabolism*; D013045:Species Specificity; D000520:alpha-Glucosidases / Q000378:metabolism
D004186:Disaccharidases; D000520:alpha-Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase