Work

Renal brush-border-membrane vesicles prepared from newborn rats by free-flow electrophoresis and their proline uptake

Year: 1983

Type: article

Abstract: A method for the isolation of brush-border membranes from newborn-rat kidney, employing centrifugation and free-flow electrophoresis, is described. The composition and purity of the preparation was assessed by determination of enzyme activities specific for various cellular membranes. Free-flow electrophoresis resolves the newborn-rat renal membrane suspension into two populations of alkaline phosphatase-enriched brush-border membranes, designated 'A' and 'B', with the A peak also showing activity of (Na+ + K+)-stimulated ATPase, the basolateral membrane marker enzyme, whereas those of the B peak were enriched 11-fold in alkaline phosphatase and substantially decreased in (Na+ + K+)-stimulated ATPase activity. Membranes in the A peak showed a 7-fold enrichment of alkaline phosphatase, and (Na+ + K+)-stimulated ATPase activity similar to that of the original homogenate. Proline uptake employed to assess osmotic dependency revealed 7% binding of proline to the B vesicles and 31% to the A vesicles. This contrasts with 60% proline binding to vesicles prepared by centrifugation alone. Unlike vesicles from adult animals, proline uptake by B vesicles did not show an Na+-stimulated overshoot, but did exhibit an Na+-gradient enhanced rate of early proline entry. proline entry.

Source: Biochemical Journal

DOI: 10.1042/bj2140209

Authors: M S Medow, K S Roth, K Ginkinger, S Segal

Institutions: Children's Hospital of Philadelphia, Virginia Commonwealth University, Virginia Commonwealth University Medical Center, University of Pennsylvania

Language: English

Topic: Ion Transport and Channel Regulation

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: bronze

Funder: National Institutes of Health

Award: GENETIC METABOLIC DISEASES OF INFANCY AND CHILDHOOD