A novel and rapid long-chain hydroxyacyl-CoA dehydrogenase assay

Abstract

INTRODUCTION Mitochondrial beta-oxidation is key physiological process in higher eukaryotes and consists of a four step reaction involving the concerted action of several chain length specifi c enzymes. Mitochondrial trifunctional protein (MTP) harbours three enzymatic activities required for the oxidation of long-chain fatty acids. Defi ciency of the second enzymatic activity of MTP, i.e. long-chain hydroxyacyl-CoA dehydrogenase activity (LCHAD), is a severe multiorgan disorder that has been included in the newborn screening programme. Identifi cation of LCHAD defi ciency occurs via the rapid and sensitive quantifi cation of acylcarnitines in plasma or serum. Although bloodspot acylcarnitine profi ling is highly indicative for this disorder, a conclusive diagnosis comes from a specifi c enzyme assay and/ or mutation analysis. However, mutation analysis is more time consuming. Measurement of LCHAD enzymatic activity is hampered by the presence of short-chain hydroxyacyl-CoA dehydrogenase (SCHAD), which also contributes to the enzymatic reaction. Therefore, we have developed and applied several means to eliminate the contribution of SCHAD. Here we report a novel, more direct, less time-consuming and less costly method.