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definitions

proactivator

[prō-ăk′tə-vā′tər]
n.
  1. A substance that, when enzymatically split, yields a fragment capable of activating another substance or process.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.