EC |
1.3.1.54 |
Accepted name: |
precorrin-6A reductase |
Reaction: |
precorrin-6B + NADP+ = precorrin-6A + NADPH + H+ |
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For diagram of corrin biosynthesis (part 3), click here |
Other name(s): |
precorrin-6X reductase; precorrin-6Y:NADP+ oxidoreductase; CobK |
Systematic name: |
precorrin-6B:NADP+ oxidoreductase |
Comments: |
The enzyme, which participates in the aerobic (late cobalt insertion) pathway of adenosylcobalamin biosynthesis, catalyses the reduction of the double bond between C-18 and C-19 of precorrin-6A. See EC 1.3.1.106, cobalt-precorrin-6A reductase, for the corresponding enzyme that participates in the anaerobic cobalamin biosynthesis pathway. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 137573-72-9 |
References: |
1. |
Blanche, F., Thibaut, D., Famechon, A., Debussche, L., Cameron, B. and Crouzet, J. Precorrin-6X reductase from Pseudomonas denitrificans: purification and characterization of the enzyme and identification of the structural gene. J. Bacteriol. 174 (1992) 1036–1042. [DOI] [PMID: 1732193] |
2. |
Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390–412. [PMID: 12195810] |
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[EC 1.3.1.54 created 1999, modified 2004] |
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EC |
1.3.1.106 |
Accepted name: |
cobalt-precorrin-6A reductase |
Reaction: |
cobalt-precorrin-6B + NAD+ = cobalt-precorrin-6A + NADH + H+ |
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For diagram of anaerobic corrin biosynthesis (part 2), click here |
Other name(s): |
cbiJ (gene name) |
Systematic name: |
cobalt-precorrin-6B:NAD+ oxidoreductase |
Comments: |
The enzyme, which participates in the anaerobic (early cobalt insertion) pathway of adenosylcobalamin biosynthesis, catalyses the reduction of the double bond between C-18 and C-19 of cobalt-precorrin-6A. The enzyme from the bacterium Bacillus megaterium has no activity with NADPH. See EC 1.3.1.54, precorrin-6A reductase, for the corresponding enzyme that participates in the aerobic cobalamin biosynthesis pathway. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Kim, W., Major, T.A. and Whitman, W.B. Role of the precorrin 6-X reductase gene in cobamide biosynthesis in Methanococcus maripaludis. Archaea 1 (2005) 375–384. [PMID: 16243778] |
2. |
Moore, S.J., Lawrence, A.D., Biedendieck, R., Deery, E., Frank, S., Howard, M.J., Rigby, S.E. and Warren, M.J. Elucidation of the anaerobic pathway for the corrin component of cobalamin (vitamin B12). Proc. Natl. Acad. Sci. USA 110 (2013) 14906–14911. [DOI] [PMID: 23922391] |
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[EC 1.3.1.106 created 2014] |
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EC |
2.1.1.132 |
Accepted name: |
precorrin-6B C5,15-methyltransferase (decarboxylating) |
Reaction: |
2 S-adenosyl-L-methionine + precorrin-6B = 2 S-adenosyl-L-homocysteine + precorrin-8X + CO2 (overall reaction) (1a) S-adenosyl-L-methionine + precorrin-6B = S-adenosyl-L-homocysteine + precorrin-7 + CO2 (1b) S-adenosyl-L-methionine + precorrin-7 = S-adenosyl-L-homocysteine + precorrin-8X |
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For diagram of corrin biosynthesis (part 4), click here |
Glossary: |
precorrin-6B = precorrin-6Y |
Other name(s): |
precorrin-6 methyltransferase; precorrin-6Y methylase; precorrin-6Y C5,15-methyltransferase (decarboxylating); cobL (gene name) |
Systematic name: |
S-adenosyl-L-methionine:1-precorrin-6B C5,15-methyltransferase (C-12-decarboxylating) |
Comments: |
The enzyme participates in the aerobic (late cobalt insertion) adenosylcobalamin biosynthesis pathway. The enzyme from the bacterium Pseudomonas denitrificans is a fusion protein with two active sites; one catalyses the methylation at C-15 followed by decarboxylation of the C-12 acetate side chain, while the other catalyses the methylation at C-5. The corresponding activities in the anaerobic adenosylcobalamin biosynthesis pathway are catalysed by EC 2.1.1.196, cobalt-precorrin-6B (C15)-methyltransferase [decarboxylating], and EC 2.1.1.289, cobalt-precorrin-7 (C5)-methyltransferase, respectively. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 162995-22-4 |
References: |
1. |
Blanche, F., Famechon, A., Thibaut, D., Debussche, L., Cameron, B., Crouzet, J. Biosynthesis of vitamin B12 in Pseudomonas denitrificans: the biosynthetic sequence from precorrin-6Y to precorrin-8X is catalyzed by the cobL gene product. J. Bacteriol. 174 (1992) 1050–1052. [DOI] [PMID: 1732195] |
2. |
Deery, E., Schroeder, S., Lawrence, A.D., Taylor, S.L., Seyedarabi, A., Waterman, J., Wilson, K.S., Brown, D., Geeves, M.A., Howard, M.J., Pickersgill, R.W. and Warren, M.J. An enzyme-trap approach allows isolation of intermediates in cobalamin biosynthesis. Nat. Chem. Biol. 8 (2012) 933–940. [DOI] [PMID: 23042036] |
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[EC 2.1.1.132 created 1999, modified 2013] |
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EC |
2.1.1.196 |
Accepted name: |
cobalt-precorrin-6B (C15)-methyltransferase [decarboxylating] |
Reaction: |
S-adenosyl-L-methionine + cobalt-precorrin-6B = S-adenosyl-L-homocysteine + cobalt-precorrin-7 + CO2 |
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For diagram of anaerobic corrin biosynthesis (part 2), click here |
Other name(s): |
cbiT (gene name); S-adenosyl-L-methionine:precorrin-7 C15-methyltransferase (C-12-decarboxylating); cobalt-precorrin-7 (C15)-methyltransferase [decarboxylating] |
Systematic name: |
S-adenosyl-L-methionine:precorrin-6B C15-methyltransferase (C-12-decarboxylating) |
Comments: |
This enzyme, which participates in the anaerobic (early cobalt insertion) adenosylcobalamin biosynthesis pathway, catalyses both methylation at C-15 and decarboxylation of the C-12 acetate side chain of cobalt-precorrin-6B. The equivalent activity in the aerobic adenosylcobalamin biosynthesis pathway is catalysed by the bifunctional enzyme EC 2.1.1.132, precorrin-6B C5,15-methyltransferase (decarboxylating). |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Keller, J.P., Smith, P.M., Benach, J., Christendat, D., deTitta, G.T. and Hunt, J.F. The crystal structure of MT0146/CbiT suggests that the putative precorrin-8w decarboxylase is a methyltransferase. Structure 10 (2002) 1475–1487. [DOI] [PMID: 12429089] |
2. |
Santander, P.J., Kajiwara, Y., Williams, H.J. and Scott, A.I. Structural characterization of novel cobalt corrinoids synthesized by enzymes of the vitamin B12 anaerobic pathway. Bioorg. Med. Chem. 14 (2006) 724–731. [DOI] [PMID: 16198574] |
3. |
Moore, S.J., Lawrence, A.D., Biedendieck, R., Deery, E., Frank, S., Howard, M.J., Rigby, S.E. and Warren, M.J. Elucidation of the anaerobic pathway for the corrin component of cobalamin (vitamin B12). Proc. Natl. Acad. Sci. USA 110 (2013) 14906–14911. [DOI] [PMID: 23922391] |
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[EC 2.1.1.196 created 2010, modified 2013] |
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EC |
2.1.1.289 |
Accepted name: |
cobalt-precorrin-7 (C5)-methyltransferase |
Reaction: |
S-adenosyl-L-methionine + cobalt-precorrin-7 = S-adenosyl-L-homocysteine + cobalt-precorrin-8 |
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For diagram of anaerobic corrin biosynthesis (part 2), click here |
Other name(s): |
CbiE |
Systematic name: |
S-adenosyl-L-methionine:precorrin-7 C5-methyltransferase |
Comments: |
This enzyme catalyses the methylation at C-5 of cobalt-precorrin-7, a step in the anaerobic (early cobalt insertion) adenosylcobalamin biosynthesis pathway. The equivalent activity in the aerobic adenosylcobalamin biosynthesis pathway is catalysed by the bifunctional enzyme EC 2.1.1.132, precorrin-6B C5,15-methyltransferase (decarboxylating). |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Santander, P.J., Kajiwara, Y., Williams, H.J. and Scott, A.I. Structural characterization of novel cobalt corrinoids synthesized by enzymes of the vitamin B12 anaerobic pathway. Bioorg. Med. Chem. 14 (2006) 724–731. [DOI] [PMID: 16198574] |
2. |
Moore, S.J., Lawrence, A.D., Biedendieck, R., Deery, E., Frank, S., Howard, M.J., Rigby, S.E. and Warren, M.J. Elucidation of the anaerobic pathway for the corrin component of cobalamin (vitamin B12). Proc. Natl. Acad. Sci. USA 110 (2013) 14906–14911. [DOI] [PMID: 23922391] |
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[EC 2.1.1.289 created 2010] |
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