A liquid chromatography mass spectrometry method for the measurement of cystathionine β-synthase activity in cell extracts

► A straightforward LC-MS/MS method for the determination of CBS enzyme activity. ► The method can be applied to different cell types. ► The method can be used for diagnosis of cystathionine β-synthase deficiency. ► The method can be used to study effects of treatment of homocystinuria. ► The method can be used to study effects of diet on mild hyperhomocystenemia.