Zonal rotor analysis of the subcellular localization of B-glycero-phosphate dehydrogenase, 1-naphthyl palmitate and 2-napthyl laurate hydrolases in the mucosa of the guinea-pig small intestine.

Whole homogenate of guinea-pig small intestine mucosa was analysed by centrifugation in a zonal rotor. The results indicate that FAD-linked a-glycerophosphate dehydrogenase is localized in the mitochondria and that NAD-linked a-glycerophosphate dehydrogenase is a soluble phase enzyme. An enzyme hydrolysing a.-naphthyl palmitate at an acid pH was localized in the Iysosomes and was activated by 0.1% Triton X-IOO and by freezing and thawing. An alkaline hydrolase acting on .B-naphthyl laurate was localized in the 'microsomes'. The possibility of this enzyme being different from a-naphthyl acetate hydrolase is discussed