Serine is a nonessential amino acid used in protein biosynthesis. In the folate cycle, glycine and serine are interconverted by the enzyme serine hydroxymethyltransferase (SHMT). Glycine accepts a methyl donor from 5-10 MTHF and becomes serine; therefore, serine is methylated glycine. [L] These methyltransferase reactions and interconversions are readily reversible depending on the needs of the folate cycle. [L]
Glycine and serine’s interconversion is important in mitochondrial glycolysis. Glycolysis provides ATP and energy in most cell types.
Serine-glycine biosynthesis is a component in glycolysis-diverting pathways and nucleotide biosynthesis. This is clinically important, and specifically evident, in cancer. Cancer cells use glycolysis to sustain anabolism for tumor growth. Genetic and functional evidence suggests that abnormalities in the glycine-serine pathway represent an essential process in cancer pathogenesis by promoting energy production and promoting defective purine synthesis. [L]
Serine is also a cofactor for the enzyme cystathionine-β- synthase making its availability important for glutathione production.
Serine can be supplied from foods or synthesized by the body from glycine and other cofactors. Serine is found in soybeans, nuts, eggs, lentils, shellfish, and meats. Dietary serine is not fully converted to glycine; therefore, supplementation has little value, though is not harmful. [L]
The clinical relevance of abnormal plasma serine is still the subject of ongoing research. However, it plays a role in the methylation balance ratio owing to the fact that it is a major methyl donor relevant to the folate pathway. Therefore, it assists in the flux of methyl groups between folate and methylation cycles.
– Kalhan SC, Hanson RW. Resurgence of serine: an often neglected but indispensable amino Acid. J Biologic Chem. 2012;287(24):19786-19791. [L]
– Amelio I, Cutruzzolá F, Antonov A, Agostini M, Melino G. Serine and glycine metabolism in cancer. Trends Biochem Sci. 2014;39(4):191-198. [L]
– Kapalka GM. Nutritional and Herbal Therapies for Children and Adolescents. Academic Press; 2010. [L]
WHAT DOES IT MEAN IF YOUR SERINE RESULT IS TOO LOW?
– Decreased dietary intake
– Malabsorption / maldigestion
WHAT DOES IT MEAN IF YOUR SERINE RESULT IS TOO HIGH?
– High dietary intake (i.e. soybeans, nuts, eggs, lentils, shellfish, and meats)
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
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