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J D Sakura

Publications and source records attributed to J D Sakura.

9 recordsLinked to original sources
PubMed1981

Physical properties of bovine white matter proteolipid apoprotein-sodium dodecyl sulfate complexes.

The interaction of bovine white matter proteolipid apoproteins with sodium dodecyl sulfate (SDS) was studied. Equilibrium dialysis binding measurements show that the apoprotein binds approximately 1.5 gm SDS per gram protein at high ionic strength (gamma/2 = 0.17). At low ionic strength (gamma/2 = 0.01) the protein binds only 0.90 gm per gram protein. The Stokes radius of the proteolipid protein is 40 A. Based on the circular dichroism spectrum, the apoprotein contains less than 20% alpha -helix structure in either aqueous or 0.1% sodium dodecyl sulfate solution. Analytical SDS-PAGE (polyacrylamide gel electrophoresis) revealed two polypeptides. The major proteolipid protein migrated with an apparent molecular weight of 26,000 daltons. The minor proteolipid protein exhibited a molecular weight of 22,200 daltons. The apoprotein showed a marked tendency to aggregate on 8 M urea-SDS-polyacrylamide gels or when heated at 100 degree in excess detergent. These results suggest that the proteolipid proteins have hydrophobic regions that are not embedded within the detergent micelle but are exposed to the solvent. These regions may serve as sites for intermolecular aggregation.

Animals↗
PubMed1976

Preparation of the proteolipid apoprotein from bovine heart, liver and kidney.

Proteolipid apoproteins have been prepared from heart, kidney, and liver by dialysis in chloroform/methanol against chloroform/methanol, acidified chloroform/methanol, and chloroform/methanol in succession. They are free of lipids (less than 0.05% P; less than 0.1% carbohydrate). They show a high content of non-polar amino acids, methionine, and tryptophan and contain little or no half-cystine. The differ from neural proteolipid apoproteins by absence of half-cystine, and of covalently bound fatty acids. As recovered from chloroform/methanol solutions, they are soluble in chloroform/methanol and insoluble in water, but a water-soluble form can be prepared by changing the solvent from chloroform/methanol to water in a stream of nitrogen. The chloroform-methanol-soluble form and the water-soluble form are interconvertible. ORD and CD spectra of all proteolipid apoproteins indicate 60-70% alpha-helix content in chloroform/methanol solution and 20-30% alpha-helix in water solution. Sodium dodecyl sulfate gel electrophoresis resolves proteolipid apoprotein into two major components corresponding to ca. 12 000 and 34 000 daltons. With sodium dodecyl sulfate/urea numerous bands appear, with a major one at 30 000 daltons and 8 to 10, ranging downward to 2500. For comparison, neural proteolipid apoproteins also show numerous bands with a major one at 25 000. The marked chemical and physical similarities among all proteolipid apoproteins studied suggest a common role in membrane structures.

Amino Acids↗