Cytochrome c aided resolution of Lupinus albus isoperoxidases in a cathodal polyacrylamide gel electrophoresis system

In a cathodal polyacrylamide gel electrophoresis system, three distinct groups of isoperoxidases from Lupinus albus were found to achieve retention factors (rf) dependent on the quantity of sample applied onto the gel. The possibility of extract-derived substances weakly associating with peroxidase samples was investigated. Association of the putative agents survived dialysis against electrophoresis buffer with and without 2 M CaCl2 and freeze-thaw treatments. The addition of polyvinylpolypyrrolidone and polyethylene glycol to the homogenization buffer also proved ineffective in eliminating the variation in isoperoxidase rf although differences in the zymogram profiles of these samples were evident. The addition of spermine and cytochrome c to samples was found to increase the rf of some peroxidase bands. Electrophoresis of samples with cytochrome c resulted in the resolution of peroxidase groups to distinct bands at rf independent of the quantity of peroxidase applied. Control experiments indicate that this treatment did not introduce any detectable artifacts.

Sialic acid residues contribute to the heterogeneity of human serum ribonuclease: demonstration by isoelectric focusing and neuraminidase treatment of serum

Ribonuclease (RNase) activity from human serum appears as multiple zones of activity following isoelectric focusing in thin layer polyacrylamide gel. At least one but not all of these zones is cross reactive with rabbit antibovine pancreatic RNase A antiserum. Treatment of serum or partially purified serum RNase with neuraminidase reduces the complexity of the serum RNase banding pattern to a major band which focuses at a pH of 9.5 or greater and a minor zone of activity which focuses at about pH 6.0-6.2. Trypsin does not affect the pattern. Thus, sialic acid residues account for a large portion of the heterogeneity of human serum RNase. Neuraminidase treatment is requisite for evaluating RNase from serum and certain other sources.