Interaction of yeast arginyl-tRNA synthetase and aspartyl-tRNA synthetase with Blue-dextran Sepharose : assignment of the Blue-Dextran Binding site on the synthetases

An efficient method for enrichment of histidyl-tRNA synthetase (Jo-1 antigen) from HeLa cells

A rapid method has been developed for enrichment of Jo-1 antigen (histidyl-tRNA synthetase) from HeLa cells. The enzyme has been prepared from post-ribosomal supernatant by successive chromatography with Blue Sepharose and Poly-U-Sepharose, followed by DEAE-high performance liquid chromatography (HPLC). By this method, enzyme could be obtained within 4 days of HeLa cell harvesting, with 40% recovery of the enzymatic activity. The apparent native molecular size of the enzyme as determined by HPLC-size exclusion column chromatography was approximately 120 kDa. Under denaturing conditions using SDS-polyacrylamide gel electrophoresis the enzyme subunit size was approximately 55 kDa. The antigen preparation, although not homogeneous, was found to react only with anti-Jo-1 positive antisera when tested by immunoblotting with many patient sera of defined autoantibody specificities, making the preparation useful for immunologic studies of anti-Jo-1 antibodies.

Dye-ligand affinity chromatography: the interaction of Cibacron Blue F3GA with proteins and enzymes

The dye Cibacron Blue F3GA has a high affinity for many proteins and enzymes. It has therefore been attached to various solid supports such as Sephadex, Sepharose, polyacrylamide, and the like. In the immobilized form the dye has rapidly been exploited as an affinity chromatographic medium to separate and purify a variety of proteins including dehydrogenases, kinases, serum albumin, interferons, several plasma proteins, and a host of other proteins. Such a diversity shown by the blue dye in binding several unrelated classes of proteins has generated considerable work in terms of studies of the chromophore itself and also the immobilized ligand. As a prelude to realizing the full potential of the immobilized Cibacron Blue F3GA, an understanding of the basic interactions of the dye with its surroundings must be gained. It has been recognized that the dye is capable of hydrophobic and/or electrostatic interactions at the instance of the ambient conditions. The study of interactions of the dye with salts, solvents, and other small molecules indicates the nature of the interactions of the dye with different kinds of groups at the interacting sites of proteins. The review will cover such interactions of the dye with the proteins, the interactions of the proteins with the immobilized ligand, and the media used to elute the bound protein in several cases, and thus consolidate the available information on such studies into a cogent and comprehensive explanation.