Microdisc-electrophoretic study of deoxyribonucleases in cow snout epidermis

Acid and neutral deoxyribonucleases (DNases) of the cow snout epidermis were investigated by the microdisc-electrophoresis of polyacrylamide gels containing highly polymerized DNA and by isoelectric focusing techniques. The nucleases were characterized with respect to their pH optimum. An acid DNase at pH 5.0 was detected as a single distinct band after the electrophoretic separation. After isoelectric focussing also, only one acid DNase activity with an isoelectric point (IP) of 6.2 was detectable. Neutral DNases at pH 7.4 were demonstrated as major and minor bands by their different electrophoretic mobilities. In the isoelectric focusing system also, two neutral DNases, a major one (IP, 4.6) and a minor one (IP, 6.4), were found. Characterization with respect to their histologic location showed acid and neutral DNases across the epidermal layers with the highest activities in the upper layers, where DNA concentration had been shown to be lowest. In correlation with their subcellular distribution, the highest activities of both acid and neutral DNase were found in the 105,00 X g supernatant of the subcellular fractions.