Bioinformatic analysis and purification of glutathione transferase (GST) from Pseudomonas sp. UW4

Abstract

The study aimed at identifying and purifying cytosolic glutathione transferase isoforms expressed in Pseudomonas sp. UW4. Search at UniProt (https://www.uniprot.org/uniprot/), has indicated that there were 20 genes encoding putative glutathione transferases for the microorganism. The molecular weights of the isoforms ranged from 17.6 to 34.06 kDa. SDS-polyacrylamide gel electrophoresis revealed that the GST purified using Sulfobromophthalein-glutathione (BSP) affinity column, resolved into a single band with a low molecular weight (MW) of 16 kDa with the pI value of 6.0. Purified GST was reactive towards ethacrynic acid, 1-chloro-2,4-dinitrobenzene, cumene hydroxide, and hydrogen peroxide, but no detectable activity with Trans-2-octenal, hepta-2,4-dienal and Trans-4-phenyl-3-butene-2-one. This has proven that putative GST possessed peroxidase activity and proposed to be similar to PputUW4_00801 (putative glutathione S-transferase) of Pseudomonas sp. UW4 according to its estimated molecular weight and the pI values obtained experimentally.