Abstract
α-Actinins which were purified from five different species of fish and rabbit skeletal muscles had the same subunit weight, approximately 100, 000, as determined by SDS-polyacrylamide gel electrophoresis.
The effect of various α-actinins on F-actin viscosity and turbidity was compared by alternating incubation temperature. It was found that an increase in rabbit F-actin viscosity with fish α-actinins occured at lower temperatures in warm to cold water adapted species. This order of the temperature dependence for fish α-actinins was the same as obtained by measuring temperature to give the maximum increase in turbidity of F-actin. Similar results were obtained when rabbit F-actin was replaced by atka mackerel F-actin. The effect of temperature was completely re-versible.
Similar temperature dependence resulted when the effect of different fish α-actinins was mea-sured in terms of actomyosin Mg2+-ATPase activity enhancement.
These findings suggest that the temperature dependence of fish α-actinin-F-actin interaction may be correlated to the environmental temperature at which the fish lives.
