Effects of lipid removal on the molecular size and kinetic properties of bovine plasma arylesterase.

摘要: A purified arylesterase preparation from bovine plasma was characterized to the extent that it has a partial specific volume of 0.91ml/g and an apparent z-average molecular weight 440000. The relatively large magnitude former reflects presence phospholipids, cholesterol, triglycerides beta-carotene, last-named being responsible for pronounced yellow colour preparation. Removal lipid material is accompanied by decrease in 120000, size smallest species detected high-speed sedimentation equilibrium vicinity 70000 daltons: denaturation lipid-free with 6m-guanidine hydrochloride caused essentially complete breakdown into subunits this size. In kinetic studies on enzyme maximal velocity hydrolysis phenyl acetate found increase 60% addition 1 mm-Ca(2+), K(m) showing concomitant 6.6 2.1 mm. had no detectable effect V(max.) or either absence Ca(2+). It concluded lipoprotein enzyme-lipoprotein complex properties very similar those alpha(1)-lipoprotein high-density (HDL(2)) fraction serum.