| Popis: |
An enzymatic activity in the microvilli of rabbit taste bud cells, which is able to hydrolyze the ATP analogue, 5'-adenylylimidodiphosphate, was studied using a lead-based cytochemical method. The reaction product appeared as round electron-dense granules on the microvillous membrane. The size of the granules increased proportionally to the incubation period, while the number of the granules remained constant (approximately 20 granules/μm^2 of the microvillous membrane). Varying the tissue-fixatives also had no effect on the number of the granules. These results indicate that a limited number of catalytic sites of the enzyme, which are presumably represented by the loci of granule formation, are evenly spaced in the membrane of the microvilli. |
