1. Rate sedimentation and isopycnic centrifugation were used to analyse the subcellular
sites of enzymes in homogenates of goldfish intestinal mucosa.
2. The results allowed the following allocations to be made: carnitine acetyl transferase-mitochondrial
and peroxisomal, xanthine dehydrogenase and NAD: :x-glycerophosphate dehydrogenase soluble phase;
NADP: isocitrate dehydrogenase soluble phase and mitochondrial, and 2-naphthyl laurate hydrolase
microsomal and/or brush border.
3. Histochemistry confirmed the use of alkaline phosphatase and I-naphthyl acetate esterase as
brush border and microsome markers respectively.
4. Urate oxidase, allantoinase, allantoicase, xanthine oxidase and glycollatejlactate oxidase, activities
were undetectable, and I-naphthyl palmilale hydrolase was present only as a contaminant from pancreas
