The Reliability of Molecular Weight Determinations by Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis¶
Why this mattered¶
Weber and Osborn’s paper helped turn SDS-polyacrylamide gel electrophoresis from a promising technique into a general measuring instrument for protein biochemistry. By showing across forty proteins that electrophoretic mobility in SDS correlated smoothly with the logarithm of polypeptide-chain molecular weight, they gave researchers a practical way to estimate subunit size without requiring purified proteins in quantities suitable for ultracentrifugation, osmometry, or other more specialized physical methods. The important shift was not simply that proteins could be separated on gels, but that a gel band could be interpreted quantitatively as evidence about a polypeptide chain’s molecular mass.
This changed what became routine in molecular biology. After this work, investigators could rapidly ask whether a protein was monomeric or composed of subunits, whether a purification step had enriched the expected product, whether a viral or cellular protein matched a predicted size, or whether proteolysis, cross-linking, mutation, or post-translational processing had altered a polypeptide. SDS-PAGE became a common language for protein identity: a visible band at an estimated molecular weight could anchor claims in enzymology, virology, cell biology, and later recombinant DNA work.
The method also fit directly into later breakthroughs because it made proteins experimentally legible at scale. Western blotting, protein purification pipelines, recombinant protein expression, membrane-protein analysis, and eventually proteomic workflows all depended on the ability to separate denatured polypeptides reproducibly and compare them against molecular-weight standards. Weber and Osborn did not invent every element of SDS-PAGE, but their systematic validation established the confidence needed for the technique to become one of the basic measurement systems of modern biology.
Abstract¶
Forty proteins with polypeptide chains of well characterized molecular weights have been studied by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate following the procedure of Shapiro, Vinuela, and Maizel (Biochem. Biophys. Res. Commun., 28, 815 (1967)). When the electrophoretic mobilities were plotted against the logarithm of the known polypeptide chain molecular weights, a smooth curve was obtained. The results show that the method can be used with great confidence to determine the molecular weights of polypeptide chains for a wide variety of proteins.
Related¶
- cite → DISC ELECTROPHORESIS – II METHOD AND APPLICATION TO HUMAN SERUM PROTEINS* — The SDS-PAGE molecular-weight study built on disc electrophoresis as the gel electrophoretic separation method for serum proteins.
- cite ← Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 — The bacteriophage T4 protein-cleavage paper relies on SDS-polyacrylamide gel electrophoresis to estimate molecular weights of viral structural proteins.
- enables ← DISC ELECTROPHORESIS – II METHOD AND APPLICATION TO HUMAN SERUM PROTEINS* — Ornstein and Davis's disc electrophoresis method supplied the polyacrylamide gel separation platform used to test SDS-PAGE molecular-weight reliability.