Isolation of two thioredoxins from the cyanobacterium Synechococcus 6301.

Two different thioredoxins designated as thioredoxin A and B have been isolated from the cyanobacterium Synechococcus 6301. Methods for large scale purification of these thioredoxins were developed. Thioredoxin B has been purified to homogeneity; it has a molecular weight of 11,800 and an isoelectric point of 4.6. The following K data were obtained for this thioredoxin; a) in the PAPS-sulfotransferase assay of Synechococcus 6301: 10.7 μM; b) in the fructose-1-6-bisphosphatase assay of Synechococcus 6301: 1.7 μM; c) in the APS-sulfotransferase assay of Chroococcidiopsis 7203: 5.4μM. Thioredoxin A has an isoelectric point of 4.1 and it is active in the PAPS-sulfotransferase and fructose-1-6-bisphosphatase of Synechococcus 6301; it is not active in the APS-sulfotransferase of Chroococcidiopsis 7203. [ABSTRACT FROM AUTHOR]