Introduction

Abstract

Interactions between actin, myosin and regulatory proteins are pivotal in muscle activation. These interactions may now be probed by ‘peptide competition’ using synthetic peptides that resemble parts of the interacting protein domains. Undoubtely, the use of peptides as molecular probes is a general approach which may be used to study many kinds of protein interactions, including, for instance, those of cell adhesion proteins, or interactions of G-proteins and immunoproteins. However, muscle tissue is particularly useful to explore the power of this approach, since the effects of altering protein interactions seem to be so obvious and so readily detectable even by mechanical measurements, and, as pointed out by Schulz and Schirmer (1978), in no other tissue are the molecular details of protein structure so readily related to the overall performance of the organ!