L-Homoserine: a novel excreted metabolic marker of hepatitis B abnormally produced in liver from methionine.

The hepatitis B infection leads to various profound pathological processes in liver metabolism. Some biochemical alterations detectable by blood analysis are currently used for a preliminary evaluation of the infection. Based on existing data we present here evidence that non-protein amino acid L-homoserine is a pathological, hepatitis B-induced metabolite that is formed and excreted into urine from methionine via splitting S-adenosylmethionine. The urine L-homoserine is proposed as a new marker in the pre-diagnosis examinations that is easier for the clinical analysis than currently used blood test, and is applicable to large-scale epidemiological surveys of the probability of hepatitis B.