Purification and Properties of 5′‐Nucleotidase from Lymphocyte Plasma Membranes

Abstract

5′‐Nucleotidase is purified from lymphocyte plasma membranes by teo affinity chromatog‐raphies. The first one, on Lens culinaris lectin‐Sepharose 4B yields a fraction of twelve lectin‐binding alyvoproteins (lectin‐receptor fractin). The second one on 5′‐AMP‐Sepharose 4B leads to pure enzyme. This enzyme is a glycoprotein with a molecular weigtht of 30000; it gives a single band in polyacrylamide/dodecylsulfte electrophoresis and displays a very high specific activity (2500–3000 μmol Pi h −1 mg −1 ). Some propertes of purified 5′‐nucleotidase are similar to those of membrance‐bound enzyme: substrate speciticity, temperature dependence, effects of ions and SH‐blocking reagents. Others are completely differnt for the teo systems and these differences result form an interaction between the enzyme molecule and other Lens culinarid lectin binding proteins.