Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
desacetylmycothiol + acetyl-CoA | Mycobacterium tuberculosis | - |
mycothiol + coenzyme-A | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Mycobacterium tuberculosis | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
desacetylmycothiol + acetyl-CoA | - |
Mycobacterium tuberculosis | mycothiol + coenzyme-A | - |
? |
General Information | Comment | Organism |
---|---|---|
malfunction | the mycothiol synthase mutant mshD::Tn5, produces high levels of Cys-GlcN-Ins along with two novel thiols, N-formyl-Cys-GlcN-Ins and N-succinyl-Cys-GlcN-Ins, and a small amount of mycothiol. The nonenzymatic reaction of acyl-coenzyme A with Cys-GlcN-Ins to produce acyl-Cys-GlcN-Ins is a facile reaction under physiologic conditions, with succinyl-CoA being an order of magnitude more reactive than acetyl-CoA. The uncatalyzed reaction rates are adequate to account for the observed production of N-succinyl-Cys-GlcN-Ins and mycothiol under physiologic conditions. The N-acyl-Cys-GlcN-Ins compounds are maintained in a substantially reduced state in the mutant but that Cys-GlcN-Ins exists in disulfide forms at 5 to 40% at different stages of growth. Mycothiol is able to facilitate reduction of N-succinyl-Cys-GlcN-Ins disulfide through thiol-disulfide exchange, but N-formyl-Cys-GlcN-Ins is ineffective. The oxidized state of Cys-GlcN-Ins in cells appears to result from a high susceptibility to autoxidation and a low capacity of the cell to reduce its disulfide forms. The mutant exhibits no enhanced sensitivity to hydrogen peroxide, tert-butyl hydroperoxide, or cumene hydroperoxide relative to the parent strain, suggesting that the most abundant thiol, N-formyl-Cys-GlcN-Ins, functions as a substitute for mycothiol | Mycobacterium tuberculosis |