tropomyosin

[trō′pə-mīə-sĭn, trŏp′ə-]
n.
  1. Any of a group of muscle proteins that bind to molecules of actin and troponin to regulate the interaction of actin and myosin.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.