Antagonistic reactions of arginine and lysine against formaldehyde and their relation to cell proliferation, apoptosis, folate cycle and photosynthesis.

1H, 13C NMR, ESMS and MS/MS investigations proved that there is an antagonism in the spontaneous reaction of formaldehyde with L-lysine and L-arginine. L-Arginine can only be hydroxymethylated on the guanidino group in a very fast reaction forming mono-, di-, and trihydroxymethyl arginines (HMA). L-Lysine can be methylated on the epsilon-amino group forming mono-, di-, and trimethyl lysine on physiological pH.

Prognostic significance of the thymidylate biosynthetic enzymes in human colorectal tumors.

The aim of the present study was to determine the relative intratumoral activity of two pyrimidine biosynthetic enzymes, i.e. thymidylate synthase (TS) and thymidine kinase (TK), in human colorectal cancers to compare their possible relationship with demographic and pathologic characteristics of the patients and their tumors, and moreover to evaluate their predictive significance regarding 5-fluorouracil (5-FU) sensitivity and the overall survival of patients, respectively.