ライフサイエンスコーパス: methylcobalamin

1 indole nitrogen in Trp during its attack on methylcobalamin.

2 pose a methyl group on substrate with one on methylcobalamin.

3 aine and cob(I)alamin to dimethylglycine and methylcobalamin.

4 and the methylation of homocysteine by free methylcobalamin.

5 o homocysteine via the enzyme-bound cofactor methylcobalamin.

6 how a protein can control the reactivity of methylcobalamin.

7 stic children were treated with 75 microg/kg methylcobalamin (2 times/wk) and 400 microg folinic acid

8 ine and tetrahydrofolate and is dependent on methylcobalamin, a derivative of vitamin B12, for activi

9 Methylcobalamin, a form of vitamin B12 was identified in

10 tic turnover numbers for the dealkylation of methylcobalamin and 5'-deoxyadenosylcobalamin by MMACHC

11 assimilation into the active cofactor forms, methylcobalamin and 5'-deoxyadenosylcobalamin, and is bo

12 The prosthetic group alternates between methylcobalamin and cob(I)alamin during catalysis as hom

13 le, the enzyme alternates between the active methylcobalamin and cob(I)alamin forms of the enzyme.

14 methylated by methyltetrahydrofolate to form methylcobalamin and demethylated by homocysteine to form

15 that targeted nutritional intervention with methylcobalamin and folinic acid may be of clinical bene

16 not treatment with the metabolic precursors, methylcobalamin and folinic acid, would improve plasma c

17 me must alternately stabilize six-coordinate methylcobalamin and four-coordinate cob(I)alamin oxidati

18 min with dimethylsulfide, yielding equimolar methylcobalamin and methanethiol in an endergonic reacti

19 ponsible for binding of the prosthetic group methylcobalamin, and amino acids 897-1227 are involved i

20 e examined the binding of adenosylcobalamin, methylcobalamin, and cob(II)alamin to the enzyme.

21 ions included vitamin B12, the B12 coenzyme, methylcobalamin, and dicyanocobyrinic acid heptamethyles

22 , in a reaction that is first-order in added methylcobalamin, and we have confirmed this observation

23 olism, the organocobalamins coenzyme B12 and methylcobalamin, are highly photolabile, as are other al

24 talyze methylation of homocysteine with free methylcobalamin as the methyl donor, in a reaction that

25 leotide substituent of the corrin ring; when methylcobalamin binds to methionine synthase, the ligand

26 by dimethylsulfide was mixed with respect to methylcobalamin, but competitive with coenzyme M.

27 ond-order rate constant for demethylation of methylcobalamin by Hcy is elevated 60-fold and that for

28 n polyacrylamide gels revealed an additional methylcobalamin:coenzyme M (methylcobalamin:CoM) methylt

29 ferase composed of two polypeptides, MtsA (a methylcobalamin:coenzyme M methyltransferase) and MtsB (

30 MtsA is an active methylcobalamin:coenzyme M methyltransferase, but also m

31 Dimethylsulfide inhibited methylcobalamin:coenzyme methyl transfer by MtsA.

32 folate to the cob(I)alamin cofactor, forming methylcobalamin cofactor and tetrahydrofolate prior to t

33 In the E. coli enzyme, the lower face of the methylcobalamin cofactor is coordinated by histidine 759

34 the enzyme transfers a methyl group from the methylcobalamin cofactor to homocysteine, generating cob

35 ormational change accompanies binding of the methylcobalamin cofactor.

36 or serine 810 decrease the reactivity of the methylcobalamin cofactor.

37 to the N termini of the A and M isozymes of methylcobalamin:CoM methyltransferase (methyltransferase

38 The methylcobalamin:CoM methyltransferase activity of the pu

39 ent molecular mass of 48 kDa which possessed methylcobalamin:CoM methyltransferase activity was detec

40 ed an additional methylcobalamin:coenzyme M (methylcobalamin:CoM) methyltransferase present in cells

41 f cob(I)alamin during turnover, to an active methylcobalamin-containing form requires a reductive met

42 cofactor for adenosylcobalamin-dependent and methylcobalamin-dependent enzymes, it plays a crucial ro

43 urally similar cobalamin-binding domain with methylcobalamin-dependent methionine synthase.

44 adenosylcobalamin-dependent isomerases, the methylcobalamin-dependent methyltransferases, and the de

45 oA was formed in reactions with CoA, CO, and methylcobalamin, directly demonstrating C-C bond activat

46 Demethylation of methylcobalamin enzyme also leads to cob(I)alamin format

47 in can also be generated by demethylation of methylcobalamin enzyme by homocysteine; it was not known

48 initially in formation of a five-coordinate methylcobalamin enzyme that slowly decays to the active

49 atalyzes the transfer of a methyl group from methylcobalamin enzyme to homocysteine, generating methi

50 rahydrofolate is already present on the free methylcobalamin enzyme.

51 t slowly decays to the active six-coordinate methylcobalamin enzyme.

52 rating tetrahydrofolate and regenerating the methylcobalamin enzyme.

53 L-methylfolate, pyridoxal 5'-phosphate, and methylcobalamin for management of endothelial dysfunctio

54 The results imply that the methylcobalamin form of MetH exists as an ensemble of in

55 e cobalt, restoring the enzyme to the active methylcobalamin form.

56 The Cys310Ala and Cys311Ala mutant methylcobalamin holoenzymes have completely lost the abi

57 The lower axial ligand to the cobalt in free methylcobalamin is the dimethylbenzimidazole nucleotide

58 hydrofolate to homocysteine via the cofactor methylcobalamin, is one of the two established mammalian

59 electrochemical (EC) reduction mechanism of methylcobalamin (Me-Cbl) in a mixed DMF/MeOH solvent in

60 reaction monitoring (MRM) and identified as methylcobalamin (Me-Cbl).

61 The B(12) cofactors methylcobalamin (MeCbl) and 5'-deoxyadenosylcobalamin (A

62 l activity of adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) is the Co-C bond cleavage step.

63 he native cofactor AdoCbl and its derivative methylcobalamin (MeCbl).

64 [H2O-Cbl], adenosylcobalamin [Ado-Cbl], and methylcobalamin [MeCbl]), only the H2O-Cbl combined with

65 nd the dealkylation of alkylcobalamins (e.g. methylcobalamin; MeCbl).

66 ing was seen between oxidized flavodoxin and methylcobalamin methionine synthase.

67 by heterolytic cleavage of the Co-C bond in methylcobalamin or the two-electron reduction of vitamin

68 y oxidation of cob(I)alamin or photolysis of methylcobalamin renders the enzyme inactive.

69 ation as the newly remethylated 5-coordinate methylcobalamin returns to the 6-coordinate state, trigg

70 ylmethionine returns the enzyme to an active methylcobalamin state.

71 djacently encoded protein, was shown to be a methylcobalamin:tetrahydrofolate methyltransferase and i

72 Binding of methylcobalamin to full-length methionine synthase is ac

73 etely abolish methyl transfer from exogenous methylcobalamin to homocysteine but do not affect methyl

74 protein catalyzes methyl transfer from free methylcobalamin to homocysteine but not from methyltetra

75 he ability to transfer the methyl group from methylcobalamin to homocysteine, suggesting that zinc is

76 es the transfer of a methyl group from bound methylcobalamin to homocysteine, yielding enzyme-bound c

77 ity to transfer methyl groups from exogenous methylcobalamin to homocysteine.

78 r ligand dimethylbenzimidazole on binding of methylcobalamin to methionine synthase, is dissociated f

79 cycle, the cobalamin-binding domain carries methylcobalamin to the homocysteine (Hcy) domain to form

80 Weak binding to methylcobalamin was indicated by the apparent Km of 14 m

81 ention trial with folinic acid, betaine, and methylcobalamin was initiated in a subset of the autisti

82 d NADPH, holoenzyme formation from apoMS and methylcobalamin was significantly enhanced.

83 methylcobinamide reacts 35-fold faster than methylcobalamin with enzyme-bound tetrahydrofolate.