An aminopeptidase N deficiency in dog small intestine

• Published in: Research in veterinary science Vol. 63; no. 2; pp. 133 - 138
• Main Authors: Pemberton, P.W, Lobley, R.W, Sørensen, S.H, Batt, R.M
• Format: Journal Article
• Language: English
• Published: England Elsevier India Pvt Ltd 01.09.1997
• Subjects: Alkaline Phosphatase - analysis; Alkaline Phosphatase - isolation & purification; alpha-Glucosidases - analysis; alpha-Glucosidases - isolation & purification; Animals; Blotting, Western - veterinary; CD13 Antigens - analysis; CD13 Antigens - isolation & purification; CD13 Antigens - metabolism; Dogs - metabolism; Electrophoresis, Gel, Two-Dimensional - veterinary; Electrophoresis, Polyacrylamide Gel - veterinary; gamma-Glutamyltransferase - analysis; gamma-Glutamyltransferase - isolation & purification; Intestine, Small - chemistry; Intestine, Small - enzymology; Intestine, Small - ultrastructure; Lactates - analysis; Lactates - isolation & purification; Membrane Proteins - analysis; Membrane Proteins - isolation & purification; Microvilli - enzymology; Microvilli - ultrastructure; Peptide Mapping - veterinary; Sucrase - analysis; Sucrase - isolation & purification
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/S0034-5288(97)90006-0

This study has identified a naturally occurring, specific deficiency of a brush border aminopeptidase N (ApN) in the small intestines of five clinically healthy dogs. ApN activity in mucosal homogenates of dog small intestine was reduced significantly in deficient animals (13·4 (1·1) nmol min −1 mg −1 protein, n = 5, P<0·002) compared to healthy control dogs (95·1 (6·7), n = 22). Alkaline phosphatase, γ-glutamyl transferase, zinc-resistant α-glucosidase, maltase, sucrase and lactase in the ApN deficient dogs exhibited comparable activities to those in the control dogs. Microvillar membranes were analysed by one- and two-dimensional electrophoresis. ApN was represented by a single 145kDa band in all control dogs, identified by immunoblotting and immunoprecipitation. Protein maps from deficient dogs Were normal apart from the virtual absence of an ApN spot and there were no apparent abnormalities in the glycosylation of microvillar proteins. The findings suggest that intestinal ApN deficiency in these dogs is a primary lesion involving diminished expression of an otherwise normal enzyme protein.