Changes in contractile muscle proteins of vitamin-E-deficient rabbits

1. 1. The optical behaviour (D.R.F.) of actomyosin, myosin and actin prepared both from normal and dystrophic rabbit muscles has been investigated. Quantitative estimations are reported. 2. 2. In dystrophic muscle myosin and actomyosin, as far as these proteins could be extracted with the method employed, do not show marked changes in the optical behaviour of their solutions as compared with normal. The only notable change requiring further investigation is the reduced increase in birefringence shown by myosin solution in 0.1−0.2 M KCl. This phenomenon may be interpreted as a change in the ability of myosin from dystrophic muscles to form K-myosinates. 3. 3. In advanced dystrophy, actin loses its capacity to be activated by different salts. This may be interpreted as an inability of actin to polymerize.