cobalamin deficiency , either nutritional or due to exposure to the co ( i ) cobalamin inactivating agent nitrous oxide , prevents the demethylation of 5-ch3-h4pteglu , which even in the presence of adequate amounts of homocysteine and methionine prevents rapidly proliferating cells from converting enough of the plasma 5-ch3-h4 pteglu into folylpolyglutamate forms to permit normal dna biosynthesis and cell replication .
C0042847
cobalamin deficiency
C0042845
cobalamin