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Literature summary for 2.5.1.151 extracted from
- A human vitamin B12 trafficking protein uses glutathione transferase activity for processing alkylcobalamins (2009), J. Biol. Chem., 284, 33418-33424 .
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| cytosol | - |
Homo sapiens | 5829 | - |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| an alkylcobalamin + [alkylcobalamin reductase] + glutathione | Homo sapiens | the enzyme is involved in the cobalamin-processing pathway. It acts as a a cytosolic cobalamin trafficking chaperone | cob(I)alamin-[alkylcobalamin reductase] + an S-alkylglutathione | - |
? |  |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Homo sapiens | Q9Y4U1 | - |
- |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 5'-deoxyadenosylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC (a cytosolic cobalamin trafficking chaperone), directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-5'-deoxyadenosylglutathione | - |
? | |
| an alkylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme is involved in the cobalamin-processing pathway. It acts as a a cytosolic cobalamin trafficking chaperone | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + an S-alkylglutathione | - |
? | |
| butyrylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-butyrylglutathione | - |
? | |
| ethylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-ethylglutathione | - |
? | |
| hexylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-hexylglutathione | - |
? | |
| methylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-methylglutathione | - |
? | |
| additional information | in addition to its dealkylase function, the enzyme also catalyses a decyanase reaction with cyanocobalamin, cf. EC 1.16.1.6, cyanocobalamin reductase (cyanide-eliminating) | Homo sapiens | ? | - |
? | |
| pentylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-pentylglutathione | - |
? | |
| propylcobalamin + [alkylcobalamin reductase] + glutathione | the enzyme can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione | Homo sapiens | cob(I)alamin-[alkylcobalamin reductase] + S-propyglutathione | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| MMACHC | - |
Homo sapiens |
Turnover Number [1/s]
| Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|
| 0.022 | - |
hexylcobalamin | pH 8.0, 20°C | Homo sapiens | |
| 0.024 | - |
pentylcobalamin | pH 8.0, 20°C | Homo sapiens | |
| 0.036 | - |
butyrylcobalamin | pH 8.0, 20°C | Homo sapiens | |
| 0.13 | - |
propylcobalamin | pH 8.0, 20°C | Homo sapiens | |
| 0.174 | - |
5'-deoxyadenosylcobalamin | pH 8.0, 20°C | Homo sapiens | |
| 1.86 | - |
ethylcobalamin | pH 8.0, 20°C | Homo sapiens | |
| 11.7 | - |
methylcobalamin | pH 8.0, 20°C | Homo sapiens | |
General Information
| General Information | Comment | Organism |
|---|---|---|
| evolution | the enzyme does not appear to be a sequence relative of either enzyme class and may have arisen by convergent evolution | Homo sapiens |
| metabolism | the enzyme is involved in the cobalamin-processing pathway | Homo sapiens |
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