EC Number   |
Substrates |
Products |
Reversibility |
|---|
  2.8.4.3 | more |
enzyme catalyzes methyl transfer from S-adenosyl-L-methionine to an acid/base labile acceptor on the protein in the absence of their respective macromolecular substrates. Denaturation of the S-adenosyl-L-methionine-treated protein with acid results in production of ethanethiol. When the enzyme is first incubated with S-adenosyl-L-methionine in the absence of substrate and reductant and then incubated with excess S-adenosyl-L-[methyl-D3]methionine in the presence of substrate and reductant, production of the unlabeled product precedes production of the deuterated product, showing that the methylated species is chemically and kinetically competent to be an intermediate |
? |
- |
? |
| 2.8.4.3 | more |
MiaB protein is a bifunctional system, involved in both thiolation and methylation of N6-dimethylallyladenine. In this process, one molecule of S-adenosyl-L-methionine is converted to 5'-deoxyadenosine, probably through reductive cleavage and intermediate formation of a 5'-deoxyadenosyl radical as observed in other radical-S-adenosyl-L-methionine enzymes, and a second molecule of S-adenosyl-L-methionine is used as a methyl donor |
? |
- |
? |
| 2.8.4.3 | more |
mechanism involves activation of an exogenous sulfur cosubstrate at an exchangeable coordination site on the second iron-sulfur cluster, which remains intact during the reaction. The enzyme has two distinct [4Fe-4S] clusters for binding and activation of two different cosubstrates. The radical-SAM cluster most likely activates SAM to form the canonical Ado· radical, as proposed for all radical-SAM enzymes, whereas the second cluster serves to activate sulfide or methylsulfide through a still-undefined mechanism |
? |
- |
? |
| 2.8.4.3 | N6-dimethylallyladenine in tRNA + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine |
substrate is a synthetic N6-dimethylallyladenine-containing RNA corresponding to the anticodon stem loop of tRNAPhe |
2-methylthio-N6-dimethylallyladenine in tRNA + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5'-deoxyadenosine |
overall reaction |
? |
| 2.8.4.3 | N6-dimethylallyladenine37 in tRNA + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine |
methylthiolation of N-6-isopentenyl adenosine in tRNAs |
2-methylthio-N6-dimethylallyladenine37 in tRNA + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5'-deoxyadenosine |
overall reaction |
? |
| 2.8.4.3 | N6-dimethylallyladenine37 in tRNA + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine |
- |
2-methylthio-N6-dimethylallyladenine37 in tRNA + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5'-deoxyadenosine |
overall reaction |
? |
| 2.8.4.3 | N6-dimethylallyladenine37 in tRNA + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine |
- |
2-methylthio-N6-dimethylallyladenine37 in tRNA + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5'-deoxyadenosine |
- |
? |
| 2.8.4.3 | N6-dimethylallyladenine37 in tRNA + sulfur-(sulfur carrier) + S-adenosyl-L-methionine |
- |
2-thio-N6-dimethylallyladenine37 in tRNA + (sulfur carrier) + L-methionine + 5'-deoxyadenosine |
- |
? |
| 2.8.4.3 | S-adenosyl-L-methionine + 2-thio-N6-dimethylallyladenine37 in tRNA |
- |
S-adenosyl-L-homocysteine + 2-methylthio-N6-dimethylallyladenine37 in tRNA |
- |
? |
