Mutations Selectively Evolving Peroxidase Activity Among Alternative Catalytic Functions of Human Glutathione Transferase P1-1.

Glutathione transferases are detoxication enzymes with broad catalytic diversity, and small alterations to the protein's primary structure can have considerable effects on the enzyme's substrate selectivity profile. We demonstrate that two point mutations in glutathione transferase P1-1 suffice to generate 20-fold enhanced non-selenium-dependent peroxidase activity indicating a facile evolutionary trajectory. Designed mutant libraries of the enzyme were screened for catalytic activities with alternative substrates representing four divergent chemistries.

Supreme glutathione-dependent ketosteroid isomerase in the yellow-fever transmitting mosquito Aedes aegypti.

The steroid hormone ecdysone is essential for the reproduction and survival of insects. The hormone is synthesized from dietary sterols such as cholesterol, yielding ecdysone in a series of consecutive enzymatic reactions. In the insect orders Lepidoptera and Diptera a glutathione transferase called Noppera-bo (Nobo) plays an essential, but biochemically uncharacterized, role in ecdysteroid biosynthesis.

Human GST P1-1 Redesigned for Enhanced Catalytic Activity with the Anticancer Prodrug Telcyta and Improved Thermostability.

Protein engineering can be used to tailor enzymes for medical purposes, including antibody-directed enzyme prodrug therapy (ADEPT), which can act as a tumor-targeted alternative to conventional chemotherapy for cancer. In ADEPT, the antibody serves as a vector, delivering a drug-activating enzyme selectively to the tumor site. Glutathione transferases (GSTs) are a family of naturally occurring detoxication enzymes, and the finding that some of them are overexpressed in tumors has been exploited to develop GST-activated prodrugs.

Versatility of Glutathione Transferase Proteins.

For more than 60 years, glutathione transferases (GSTs) have attracted attention, but the research field of the GSTome [...

Conservation of Glutathione Transferase mRNA and Protein Sequences Similar to Human and Horse Alpha Class GST A3-3 across Dog, Goat, and Opossum Species.

The glutathione transferase A3-3 (GST A3-3) homodimeric enzyme is the most efficient enzyme that catalyzes isomerization of the precursors of testosterone, estradiol, and progesterone in the gonads of humans and horses. However, the presence of GST A3-3 orthologs with equally high ketosteroid isomerase activity has not been verified in other mammalian species, even though pig and cattle homologs have been cloned and studied. Identifying genes is a challenge because of multiple gene duplications (e.