when maltase and gp330 were localized by indirect immunofluorescence and by indirect immunoperoxidase and immunogold techniques at the electron microscope level , they were found to be differently distributed in the brush border of the initial ( s1 and s2 ) segments of the proximal tubule : maltase was concentrated ( approximately 90 % ) on the microvilli , and gp330 was concentrated ( approximately 90 % ) in the clathrin-coated apical invaginations located at the base of the microvilli .
C1318418
brush border
C0026049
microvilli