A Computational Comparative Study of Α-Glucosidase Enzyme Divergence

Abstract

α-glucosidases (α-Gls) catalyze the last step of carbohydrate digestion in mammals and release glucose in bloodstream, which results in the increased blood glucose level. The evolution and classification of this enzyme has been a matter of debate. In the present study the amino acid sequences of α-Gls from 12 species were aliened and the Phylogenetic trees were constructed. The data indicated that only the mammalian enzyme contained the glucoamylase region. Five amino acid regions were found to be the conservative blocks of mammalian α-Gls. These blocks were not fully conserved in plants, fungi and bacteria. The results were in favor of Chibas classification despite the Ile→Thr substitution in Aspergillus Niger and Ala→Pro substitution in chimpanzee and human α-Gls. The chimpanzee α-Gls showed the most similarity to human enzyme. Plants, fungi, bacteria, and the mammalian α-Gls seemed to separately create a specific class. Together, the data suggest that the eukaryotic enzyme had been diverged significantly from the prokaryotic α-Gls since the separation from the common ancestor.