Figure 1.
Biochemical pathways for the interaction of folate metabolism and the S-adenosylmethionine (SAM) cycle.
Dietary folate is metabolized to 5-methyltetrahydrofolate (5-MTHF), which is used by methionine synthase for the conversion of homocysteine to methionine. Methionine can also be synthesized from betaine, especially in liver tissue. Catabolism of the folates by cleavage of the C9-N10 bond produces p-aminobenzoylglutamate (PABG) and pterin (not shown). Murine Nat2 (and human NAT1) acetylates PABG to N-acetyl-PABG, which is a major folate metabolite found in the urine.
Figure 2.
Tissue concentrations of 5-MTHF (A), Hcy (B) and methionine (C) in C57BL/6J mice.
The open bars are male tissue samples while the solid bars are female tissue samples. Results are mean ± SEM, n = 3. Asterisk indicates significant difference compared to respective male concentrations (p<0.05).
Figure 3.
Tissue concentrations of SAM (A) and SAH (B) in C57BL/6J mice.
The open bars are male tissue samples while the solid bars are female tissue samples. Results are mean ± SEM, n = 3. Asterisk indicates significant difference compared to respective male concentrations (p<0.05).
Figure 4.
Liver and kidney concentrations of PABG (A) and N-acetyl-PABG (B) in C57BL/6J mice.
(C) Relative NAT1 mRNA levels determined by qPCR. The open bars are male tissue samples while the solid bars are female tissue samples. Results are mean ± SEM, n = 3. Asterisk indicates significant difference compared to respective male concentrations (p<0.05).
Figure 5.
Tissue concentrations of 5-MTHF (A), Hcy (B) and methionine (C) in male and female Nat2−/− C57BL/6J mice.
Results are mean ± SEM, n = 3, and are expressed as percentage of wild-type concentrations. Asterisk indicates significant difference compared to respective wild-type concentrations (p<0.05).
Figure 6.
Tissue concentrations of SAM (A) and SAH (B) in male and female Nat2−/− C57BL/6J mice.
Results are mean ± SEM, n = 3, and are expressed as percentage of wild-type concentrations. Asterisk indicates significant difference compared to respective wild-type concentrations (p<0.05).
Figure 7.
Liver and kidney concentrations of PABG in male and female Nat2−/− C57BL/6J mice.
Results are mean ± SEM, n = 3, and are expressed as percentage of wild-type concentrations.