Mycobacterium tuberculosis CysA2 is a dual sulfurtransferase with activity against thiosulfate and 3-mercaptopyruvate and interacts with mammalian cells.

Cyanide is a toxic compound that is converted to the non-toxic thiocyanate by a rhodanese enzyme. Rhodaneses belong to the family of transferases (sulfurtransferases), which are largely studied. The sulfur donor defines the subfamily of these enzymes as thiosulfate:cyanide sulfurtransferases or rhodaneses (TSTs) or 3-mercaptopyruvate sulfurtransfeases (MSTs). In Mycobacterium tuberculosis, the causative agent of tuberculosis, the gene Rv0815c encodes the protein CysA2, a putative uncharacterized thiosulfate:cyanide sulfurtransferase that belongs to the essential sulfur assimilation pathway in the bacillus and is secreted during infection. In this work, we characterized the functional and structural properties of CysA2 and its kinetic parameters. The recombinant CysA2 is a α/ß protein with two rhodanese-like domains that maintains the functional motifs and a catalytic cysteine. Sulfurtransferase activity was determined using thiosulfate and 3-mercaptopyruvate as sulfur donors. The assays showed Km values of 2.89 mM and 7.02 mM for thiosulfate and 3-mercaptopyruvate, respectively, indicating the protein has dual activity as TST and MST. Immunological assays revealed that CysA2 interacted with pulmonary cells, and it was capable to activate macrophages and dendritic cells, indicating the stimulation of the immune response, which is important for its use as an antigen for vaccine development and immunodiagnostic.

Production and characterization of a monoclonal antibody to bovine estrogen sulfotransferase.

A murine IgGl (k) monoclonal antibody, termed 33-11, was produced against purified bovine estrogen sulfotransferase. After the enzyme was separated into its four isoenzyme forms by native polyacrylamide gel electrophoresis, a Western blotting analysis indicated that the antibody reacted to a similar extent with each of the isoenzymes. An immunoprecipitation and SDS-poly acrylamide gel electrophoresis analysis was performed with an I-125-labeled enzyme preparation. Antibody 33-11 precipitated protein in the molecular weight range 70,000-74,000, the size of native estrogen sulfotransferase, plus additional bands with molecular weights of 29,000, 54,000, and 61,000. The lower molecular weight polypeptides may represent fragments, bearing a common epitope, produced by limited endogenous proteolysis of the intact enzyme. Solid-phase radioimmunoassay testing demonstrated strong and specific binding of the antibody to the bovine enzyme. No cross-reactivity was observed with a panel of nine other purified bovine proteins. An immunohistochemical analysis with the antibody was performed on two bovine tissues with high levels of enzyme activity. Placenta showed strong, specific staining of fetal giant cells of chorionic villi, while adrenal had weak but widespread staining which tended to be more concentrated in the inner cortex. Monoclonal antibody 33-11 has potential utility in the purification, detection, and quantitation of bovine estrogen sulfotransferase.

Rat hepatic bile acid sulfotransferase: enzyme response to androgens and estrogens.

Rat liver bile sulfotransferase activity can be divided into a fraction that reacts with a monoclonal antibody (PK1B) and another fraction that does not. This work was performed to analyze the known response of hepatic bile acid sulfotransferase activity to androgens and estrogens by determining the effect of treatment on the proportion of bile acid sulfotransferase activity that possessed the epitope for PK1B monoclonal antibody. Activity in treated animals was further characterized by high-performance liquid chromatography (HPLC) analysis following purification by PK1B-immunoadsorption chromatography. The results indicate that estrogens and androgens affect the subset of enzyme activity that has the PK1B epitope more than the population that does not. HPLC demonstrates that increases and decreases in activity that follow treatment with androgens and estrogens are mirrored by the proportion of the PK1B-reactive protein that exhibits a relative molecular weight (Mr) greater than 170,000. Radial immunodiffusion assays of hepatic supernatant using a polyclonal antibody raised against PK1B-reactive bile acid sulfotransferase show that changes in specific activity that follow treatment are the result of changes in enzyme protein concentration.