USE OF SODIUM DODECYL SULFATE, ALONE, TO SEPARATE CHROMATIN PROTEINS FROM DEOXYRIBONUCLEOPROTEIN OF ARBACIA PUNCTULATA SPERM CHROMATIN

A method using sodium dodecyl sulfate to extract about 90% of the chromatin protein from a remaining deoxyribonucleoprotein of Arbacia punctulata sperm chromatin is described. More than 92% of the extracted protein could be concentrated extensively by lyophilization in the presence of sodium dodecyl sulfate and reduced to a sodium dodecyl sulfate to protein weight ratio of 0.1000 via a urea dialysis- BaCl2 precipitation procedure. This protein was readily separated into six distinct fractions in the presence of BaCl2 using acrylamide disc gel electrophoresis. Five of the fractions were histone while a sixth contained acidic protein. The remaining 8% of the extracted protein could be redissolved in Lowry C reagent from a precipitate induced by BaCl2 for the elimination of sodium dodecyl sulfate. Precipitated protein, after redissolving in this reagent, behaved electrophoretically like nonprecipitated protein. Once electrophoretically fractionated, the sodium dodecyl sulfate to protein ratio of the protein components could be further reduced by dialysis. The method is capable of yielding 100% of the fractionated chromatin protein in soluble form. It may be used to analyze chromatin into its component parts for their further chemical or physical probing or for reconstitution studies. Sodium dodecyl sulfate also provides a way to examine the deoxyribonucleic acid melting profile of chromatin or nucleoprotein preparations without having to first extract the deoxyribonucleic acid from the preparations. © 1969, American Chemical Society. All rights reserved.