Method for the determination of amp;agr;-ketoisocaproate in biological samples using D-amp;agr;-hydroxyisocaproic dehydrogenase from lactobacillus casei

摘要

The selective determination of &agr;-ketoisocaproate in samples of body fluids, especially in serum, is achieved, without previous separation, directly in the fluid and in the presence of NADH, by means of a KIC-specific D-&agr;-hydroxy-isocaproic dehydrogenase that originates specifically from strains of Lactobacillus casei producing this enzyme, in particular strains of Lactobacillus casei subspecies pseudoplantarum or casei. The KIC determination is used, in particular, for diagnosing maple syrup urine disease. Expedient for this purpose are analytical kits which have a divisible stock of D-&agr;- hydroxyisocaproic dehydrogenase from Lactobacillus casei, in particular from the Lactobacillus casei (DSM 20008).