Fig. 6

Distribution of metabolic enzymes in mouse proximal intestine. a) Enzymatic activities (Units/mg of protein) of aminopeptidase N and the NADPH cytochrome C reductase, in the I homogenate, the Mi/Ba membranes and the BBM of mouse enterocytes : means ± SD of three separate experiments. b) Detection by Western-blots of MTTP, MGAT2, DGAT1 and UGT1A in the same three samples. For the electrophoresis, equivalent amounts of proteins were loaded and molecular weights are noted in kDalton (kDa). c) Immuno-fluorescent detection of MGAT2 (green) in proximal jejunum associated to membrane staining with WGA- Alexa Fluo 594 (red) which permitted a clear localization of the BBM and to DAPI (blue) for nucleus identification. The merge images showed a spread and punctuated distribution of MGAT2, from the basolateral (BM) to the sub-apical membranes, but also inside the BBM. To underlight this dual localization the intensity of fluorescence of MGAT2 and WGA were quantified in a ROI crossing an enterocyte. Ent: enterocytes, Lu: lumen, LP: lamina propria. The experiments shown are representative of 3 (a, b) or 2 (c) separate experiments