A VERSATILE NEGATIVE-STAINING RIBONUCLEASE ZYMOGRAM

A versatile negative-staining ribonuclease zymogram is described. The method has several advantages as it combines, by means of different st aining procedures, high resolving power, sensitivity, and specificity with a rapid, reproducible, and simultaneous analysis of purity of rib onuclease samples on the same polyacrylamide gel. Activity bands can b e visualized at any time during the incubation process without stainin g of the gel. This allows the choice of different staining procedures after incubation. Using poly(C) as substrate less than 1 pg of bovine pancreatic ribonuclease A was detected in less than 2 h after the elec trophoretic run. An additional advantage with respect to other methods is that no refrigeration is needed during electrophoresis. (C) 1994 A cademic Press, Inc.