Radiation inactivation probe of membrane-bound enzymes: gamma-glutamyltranspeptidase, aminopeptidase N, and sucrase
gamma-Glutamyltranspeptidase (GGT), aminopeptidase N (AP-N), and sucrase in purified rabbit intestinal brush border membrane vesicles were irradiated in situ at -135 degrees C using high energy electrons. Surviving activities of the enzymes were measured as a function of radiation dose, and the functional unit target sizes (corresponding to carbohydrate-free polypeptides) were determined using target analysis. The in situ functional unit sizes were GGT 59 kDa, AP-N 59 kDa, and sucrase 63 kDa. Together with biochemical data determined previously, it is concluded that the noncovalently attached large (approximately 40 kDa) and small (approximately 25 kDa) subunits of GGT are both required for catalytic activity. Furthermore, these data suggest that (i) the membrane-bound form of AP-N consists of one or more noncovalently attached subunits of 59 kDa, each of which is enzymatically active; and (ii) in situ sucrase activity is associated with a subunit of 63 kDa which is noncovalently attached within the sucrase-isomaltase complex.
- Research Organization:
- Univ. of Florida College of Medicine, Gainesville
- OSTI ID:
- 6936515
- Journal Information:
- Anal. Biochem.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Knockdown of laminin α5 stimulates intestinal cell differentiation
Intestinal mucosa in diabetes: synthesis of total proteins and sucrase-isomaltase
Related Subjects
AMINOPEPTIDASES
BIOLOGICAL RADIATION EFFECTS
PEPTIDE HYDROLASES
CELL MEMBRANES
DOSE-RESPONSE RELATIONSHIPS
ENZYME ACTIVITY
IN VITRO
INACTIVATION
INTESTINES
RABBITS
ANIMALS
BIOLOGICAL EFFECTS
BODY
CELL CONSTITUENTS
DIGESTIVE SYSTEM
ENZYMES
GASTROINTESTINAL TRACT
HYDROLASES
MAMMALS
MEMBRANES
ORGANS
RADIATION EFFECTS
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture