PMID: 1194272Dec 10, 1975Paper

Effect of cytochrome b5 on the size, density, and permeability of phosphatidylcholine vesicles

The Journal of Biological Chemistry
P W Holloway, J T Katz

Abstract

Cytochrome b5, isolated from rabbit liver by a procedure using detergent, was incubated with phosphatidylcholine bilayer vesicles at 37 degrees for 30 min. A comparison of a number of physical properties was made between the cytochrome b5-phosphatidylcholine complex (at a molar ratio of 1:1000) and the phosphatidylcholine vesicles. The binding of the protein to the vesicle caused no aggregation and no detectable change in Stokes radius of the vesicle as monitored by gel filtration. Only small increases in s20 (from 2.67 up to 3.82 X 10(-13) s) and density (from 1.025 up to 1.042 g ml(-1)) were observed upon binding of the cytochrome b5 to phosphatidylcholine vesicles. At molar ratios of 5:1000, and above, two types of complexes could be detected by sucrose density gradient centrifugation: one had a molar ratio of approximately 1.066 g ml(-1)) the other, a more constant ratio of 20:1000 (density greater than 1.107 g ml(-1)). Cytochrome b5 was also incubated with phosphatidylcholine vesicles prepared with ferricyanide trapped inside. The leakage of the ferricyanide from inside the vesicles was increased when cytochrome b5 was present, but the vesicles, although leaking, were not completely depleted of their ferricyande, and so mu...Continue Reading

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.