Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products. Four major components of the head are cleaved during the process of assembly, apparently after the precursor proteins have assembled into some large intermediate structure.

Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4

Cleavage of structural proteins during the assemble of the head of bacterio-phage T4

The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis

High resolution two-dimensional electrophoresis of proteins.

Summary

The technique of disc electrophoresis has been presented, including a discussion of the technical variables with special reference to the separation of protein fractions of normal human serum.

Disc electrophoresis – ii method and application to human serum proteins*

SummaryA high resolution technic is described for localization of intracellular sites of erythrocyte esterases. Blood smears are fixed in 1% osmium tetroxide in dimethylformamide at −15°C and then incubated in medium containing alpha naphthyl acetate and “hexaazotized” pararosanilin. Alpha naphthol released by enzymatic hydrolysis of the substrate ester couples with “hexaazonium”salt to form a colored, insoluble, amorphous deposit at sites of esterase activity.

Histochemical demonstration of erythrocyte esterases.

Electrophoretic process for simultaneously spearating and concentrating particles

The separation of mixtures of proteins by disc electrophoresis or acrylamide' is highly efficient. Bands representing different protein fractions are sharply defined and permit the recognition of specific proteins that possess similar electrophoretic mobility. The size of each band is related to the concentration of that protein in the mixture. This method is especially useful in detecting small quantities of contaminants during the purification of proteins2*8 as well as in the separation and analysis of enzymes.' Over 25 distinct components can be visualized in normal human serum by a modification of the original technique of Ornstein and Davis.5 Both methods were used by Zingale et a2.O for analysis of elevated serum globulins in myeloma and macroglobulinemia, but the electrophoretic heterogeneity of myeloma proteins, demonstrated by Fahey' in starch gel, could not be duplicated in acrylamide. The present study was undertaken to determine the usefulness of another modification of this method by (a ) establishing characteristic patterns for different types of paraproteinemias; (b) correlating the size and the shape of the protein molecules and their solubility in low ionic strength buffers with their penetration into the separation gel; (c) identifying the paraproteins in other body fluids (i.e., urine and cerebrospinal fluid); and (d) comparing isolated components from the serum and urine of the same patient. For the purpose of this presentation, representative samples of each group of proteins were selected from a comprehensive study (to be published elsewhere) of the abnormal proteins in hematological disorders. Cases were classified on the basis of ultracentrifugal and immunoelectrophoretic analysis of the abnormal component, clinical findings, and blood and bone marrow examinations. In addition to the y and p myelomas and macroglobulinemias, two unusual paraproteins were selected for detailed presentation. In using the original method,' in which the sample is applied directly to the top of the separation gel, part of the paraprotein could not be accounted for in all cases of Waldenstrom macroglobulinemia and some cases of multiple myeloma. Although one or more dense bands were seen at, or just below, the origin of the separation gel, the relative concentration of macroglobulin was found to be much lower than that obtained by ultracentrifugal analysis. Similarly, close inspection of the photographs published by Zingale6 appears to show a greater amount of protein material penetrating the gel after dissociation of the macroglobulin by sulfhydryl reagents than is visible on the top of the gel prior to splitting of the intact protein. On the other hand, when the sample was separated on acrylamide by the modified technique of Ornstein and Davis,5 in which, in addition to the separation gel, both spacer and application gels are used, the line on the top of the separating gel was not visible. Here, too, bands penetrating the separation gel could not account for the large quantity of macroglobulin known to be present in some sera. It was assumed therefore that this component was at least partially retarded

Baruch J. Davis

Papers

Disc electrophoresis – ii method and application to human serum proteins*

Histochemical demonstration of erythrocyte esterases.

Electrophoretic process for simultaneously spearating and concentrating particles

Abnormal proteins and protein fractions in myeloma.