EC Number   |
Reaction |
Reference |
|---|
    2.1.1.2 | S-adenosyl-L-methionine + guanidinoacetate = S-adenosyl-L-homocysteine + creatine |
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- |
| 2.1.1.2 | S-adenosyl-L-methionine + guanidinoacetate = S-adenosyl-L-homocysteine + creatine |
computer model of the reaction mechanism: by self-consistent-charge density functional tight binding/molecular mechanics, the bond lengths in the concerted mechanisms transition state is 1.26 A for both the OD1 (Asp-134)-HE (guanidinoacetate) and HE (guanidinoacetate)-NE (guanidinoacetate) bonds, and 2.47 and 2.03 A for the S8 (S-adenosyl-L-methionine)-C9 (S-adenosyl-L-methionine) and C9 (S-adenosyl-L-methionine)-NE (guanidinoacetate) bonds, respectively. The potential-energy barrier (delta E++) determined by single-point B3LYP/6-31+G*//MM is 18.9 kcal/mol. The contributions of the entropy (-TdeltaS++) and zero-point energy corrections delta(ZPE)++ by normal mode analysis are 2.3 kcal/mol and -1.7 kcal/mol, respectively. The activation enthalpy of this concerted mechanism is deltaH++ = 17.2 kcal/mol. The calculated free-energy barrier for the concerted mechanism is deltaG++ = 19.5 kcal/mol. |
676826 |
| 2.1.1.2 | S-adenosyl-L-methionine + guanidinoacetate = S-adenosyl-L-homocysteine + creatine |
mechanism |
661103 |
| 2.1.1.2 | S-adenosyl-L-methionine + guanidinoacetate = S-adenosyl-L-homocysteine + creatine |
the hybrid density functional theory (DFT) method B3LYP is used to examine the reaction mechanism: The methyl group transfer from S-adenosylmethionine to NE of guanidinoacetate occurs concertedly with a proton transfer from NE to the neighboring OD1 of Asp134. |
675612 |
