Sulfur Metabolism and its Clinical Correlations

Objective. My talk would cover overall sulfur metabolism and various clinical correlations of sulfur biology including cancer. Background. Sulfur is one of the chief elements that are required for normal biological functions. From archaea to mammals importance of sulfur has been realized. Sulfur in the form of inorganic anion (sulfate) is specifically transported from extracellular milieu into intracellular regions. Once inside the cell it is reduced into sulfide by complex sets of enzymes. The reduced sulfide is then incorporated into carbon compounds for example in the form of the amino acid, methionine. The sulfate reduction and de novo synthesis of methionine is absent in mammals. Thus methionine is an essential amino acid for mammals that would have to come from diet especially during development and cell divisions. Inorganic sulfate can also be converted to 3’-phosphoadenosine 5’- phosphosulfate (PAPS) using ATP by PAPS synthase in two sequential steps. PAPS is the universal sulfuryl donor. Methods. Enzyme assays of PAPS synthase and Methionase will be discussed. Results. PAPS synthase and Methionase are two key enzymes of sulfur metabolism. Conclusion. There are many small molecules as well as macromolecules that get sulfonated by respective sulfotransferases. Once sulfonated the physico-chemical properties of the recipient compounds is altered. Deficiency in sulfonation can lead to serious diseases like skeletal deformity. Grants. HPD and PFR&D of NSU.