| antivitamin | A substance that prevents a vitamin from exerting its typical biological effects. Most antivitamin's have chemical structures similar to vitamins (e.g., pyridoxine and its antivitamin, deoxypyridoxine) and appear to function as competitive antagonists; some antivitamin's produce effects, in addition, that are unrelated to vitamin antagonism. (05 Mar 2000) |
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