Alterations of intestinal glycoprotein hydrolases in congenital diabetes

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6413270

Najjar, S M

The diabetic BioBreed (BB{sub d}) rat was used for the study of the molecular structure of intestinal brush border sucrase-{alpha}-dextrinase (SD) and aminooligopeptidase (AOP) in diabetes mellitus. The specific catalytic activity of S-D and AOP in the BB{sub d} rat is normal. However, solid-phase radioimmunoassay revealed loss of some antigenic determinants in the BB{sub d} rat. S-D and AOP migrated abnormally on 6% SDS-gel electrophoresis in the BB{sub d} rat. S was larger (+5 kDa), D was either smaller (-5 kDa) or unaltered, and AOP was smaller (-5 kDa) in the BB{sub d} than in the normal Wistar. The structural abnormalities were independent of hyperglycemia or ketoacidosis and restored to normal by daily insulin treatment (NPH, 3-4 units/rat) for two to three weeks. Newly-synthesized brush border hydrolases were examined after 6 hours of intraperitoneal injection of ({sup 35}S) methionine (2 mCi) and found to be altered, suggesting that structural abnormality appeared acutely during intracellular synthesis rather than being due to slow extracellular modifications such as non-enzymatic glycosylation. Deglycosylation of brush border proteins by trifluoromethanesulfonic acid resulted in an apoprotein with normal electrophoretic migration in BB{sub d}, indicating that the alteration was due to the carbohydrates component of the glycoprotein. Pulse-chase studies with ({sup 35}S) methionine were consistent with normal protein an co-translational and initial N-linked carbohydrate assembly in association with the endoplasmic reticulum in BB{sub d}. However, the post-translational maturation of N-linked and addition of 0-linked carbohydrate chains in Golgi were prolonged, and produced a larger single-chain precursor of S-D in BB{sub d} than normal.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 6413270
• Country of Publication: United States
• Language: English

Related Subjects

550901* -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOASSAY
BODY
CARBOXYLIC ACIDS
CONGENITAL DISEASES
DAYS LIVING RADIOISOTOPES
DIABETES MELLITUS
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DISEASES
DRUGS
ELECTROPHORESIS
ENDOCRINE DISEASES
ENZYMES
EVEN-ODD NUCLEI
GASTROINTESTINAL TRACT
HORMONES
HYDROLASES
IMMUNOASSAY
IMMUNOLOGY
INSULIN
INTESTINES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
METABOLIC DISEASES
METHIONINE
MOLECULAR STRUCTURE
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PATHOGENESIS
PEPTIDE HORMONES
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNODETECTION
RADIOIMMUNOLOGY
RADIOISOTOPES
RATS
RODENTS
SULFUR 35
SULFUR ISOTOPES
TRACER TECHNIQUES
VERTEBRATES