Urea
tetrahydrofolate
6-methyl pterin
P-aminobenzoate
glutamate
valerate
N5 and N10
methenyl 亚甲基
formyl 甲酰基
formimino 亚胺甲基
serine to glysine
SAM ATP and methionine
methionine adenosyl transferase
the neucleophillic
Creatine kinase
biotin carbon dioxide
tetrahydrofolateintermediate oxidation states /methyl group methionine adenosyl transferase nuceophilic sulfur attack the 5' carbon and release triphosphate Pi and PPi, PPi then be degraded into two inorganic phosphate synthesis of coenzyme B12 Sulfonium ion