Characters of Amino Acid Substitutions in LDH-A and LDH-B in the Evolutionary Line of Vertebrates

Structure of lactate dehydrogenase LDH-A (muscle) and LDH-B (heart) subunits is compared in the evolutionary line of vertebrates from Chondrosteous fishes to Mammals. It is revealed persistent differences between them in the amino acid set determining the physical and chemical characteristics of macromolecules. The polypeptide chain of LDH-A is shorter then that of LDH-B but it contains amino acids with higher molecular weight. In LDH-A polarized amino acids are less in number but charged amino acids are more numerous, positive charged amino acids prevail over negative charged ones. The features of polypeptide structure are discussed in connection with differences in the level of intraspecific variability of allozymes in the evolutionary line of vertebrates.

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