Immobilized pH gradient focusing of alkaline proteins: analysis of the isoform composition of purified human non-secretory ribonucleases from kidney, liver and spleen

pH gradient electrophoresis of basic ribonucleases in sealed slab polyacrylamide gels: detection and inhibition of enzyme activity in the gel

A simple method for the separation and specific detection of basic ribonucleases (RNases) was developed. The separation was achieved by polyacrylamide gel electrophoresis in a pH gradient generated by a carrier ampholyte (Pharmalyte 8-10.5) and arginine. In order to prevent interference from atmospheric carbon dioxide, the pH gradient was formed in sealed vertical gel slab. Human nonsecretory-type RNase, bovine pancreatic RNase A, and other basic proteins could be resolved without expensive equipment or complicated procedures. For activity detection after electrophoresis a zymogram technique was applied, using dry agarose film containing ethidium bromide plus RNA as substrate. This approach affords two advantages: (i) Basic RNase activities can be detected within 15 min, even in crude materials. The sensitivity is better than 0.5 ng of purified human nonsecretory-type RNase. (ii) An inhibition test of RNase activities in the gel, using human placental-type RNase inhibitor, can be performed.

Solute focusing techniques for bioseparations

The growth of industrial biotechnology has had a major impact on the research and development of both analytical and preparative focusing techniques. Pioneering methods such as isoelectric focusing are being modified to overcome the limitations of batch mode operation, scale up difficulties, high power requirement, and excessive heat generation. present advances in focusing techniques have been made by either overcoming the limitations of standard techniques or by investigating new focusing systems. Here we review the background and history of isoelectric focusing and discuss several new focusing techniques including recycle isoelectric (RIEF), counteracting chromatographic electrophoresis (CACE), and countercurrent gradient chromatography (CGC).