Renaturation of enzymes after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.

Abstract

A number of enzymes, including amylases, dehydrogenases, and proteases, were shown to be renaturable after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Enzyme activity was detected in situ by action on substrates introduced into the gel and subsequent staining of either the product or unreacted substrate. This technique combines the advantage of enzyme identification with the resolution and molecular weight dependence of gel electrophoresis in the presence of sodium dodecyl sulfate. Enzymes appeared to recover activity as soon as the detergent diffused out of the gel. Most monomeric enzymes could be renatured even after disruption of their disulfide bonds, but several proteases, including trypsin, could not. Oligomeric enzymes composed of identical subunits were poorly renaturable. Renatured enzymes were retained in gels after electrophoresis longer than native enzymes which had been subjected to electrophoresis in the absence of detergent. Re-electrophoresis of the renatured enzymes showed that part of the retained activity was physically anchored to the gel, possibly by the folding of polypeptide aroung the gel matrix as the enzymes were renatured.