Enzymatic determination of serum-free fatty acids: a colorimetric method

A simple and sensitive enzymatic method is described for the determination of serumfree fatty acids. The method is based on the activation of free fatty acids by acyl-CoA synthetase (EC 6.2.1.3). The reaction is followed as the production of hydrogen peroxide by using acyl-CoA oxidase/peroxidase/4-aminoantipyrine/phenol system. Results on human sera correlate well with those obtained by our previously described enzymatic method (Shimizu et al. (1979) Anal. Biochem.98, 341–345) and the chemical colorimetric method.