Calcium-Binding Proteins

Abstract

Numerous low molecular weight albumins occurring in the white muscle of fish have been characterised according to biochemical properties^283,284. While the physiological function of these proteins of approximately 11 000 molecular weight is not known, they manifest unusual characteristics in having amino-acid compositions of approximately 10 per cent phenylalanine and 20 per cent alanine content with little or no tryptophan, tyrosine, methionine, histidine, cysteine or arginine. In addition, they exhibit high calcium affinity. These two characteristics suggest that the carp-albumin protein may be analogous to the troponin-A protein of mammalian and avian muscle²⁸⁵, and may be involved, therefore, in mediation of the effect of calcium in muscle contraction²⁸⁶.