The quantitation of rat serum esterases by densitometry of acrylamide gels stained for enzyme activity.

Normal rat sera were electrophoresed on polyacrylamide gels. The gels were then stained for (a) esterase activity and (b) protein content. Subsequent analysis on a densitometer permitted quantitative estimation of both enzyme activity and protein concentration. (The specific activity (per mg of protein) of individual serum esterases were then calculated.) Two previously unreported esterases (Bands A and D), were identified and partially characterized. When carefully prepared, non-activated plasma was used, no differences in enzyme activity were found compared to serum.