Comparative study on brush border membranes prepared from rat and monkey small intestine by Ca²⁺ and Mg²⁺ precipitation

Abstract

Brush border membranes, prepared by Ca²⁺ or Mg²⁺ precipitation, from monkey or rat small intestine were compared for marker enzyme enrichment and lipid composition. Membranes prepared from rat intestine by Mg²⁺ precipitation were less pure in terms of their marker enzyme enrichment than Ca²⁺ precipitated membranes. Moreover, Mg²⁺ precipitated membranes were contaminated by basolateral membranes as evidenced by the enrichment of Na²⁺−K²⁺ ATPase. The content and composition of phospholipids were different in Mg²⁺ and Ca²⁺ precipitated membranes. The membranes prepared by the two methods from monkeys were identical in their marker enzyme enrichment and lipid composition and unlike those obtained from the rat, there was no basolateral membrane contamination.