Bioinformatical study of 134th amino acid position role on substrate specificity of dihydroflavonol 4-reductase in anthocyanins biosynthesis

Plant colors are basically three categories of flavonoid، carotenoid and betalains. Flavonoid and in particular anthocyanins are main colored pigments of flower، fruits and seeds. Biosynthetic pathway leading to biosynthesis of anthocyanin among species is well conserved. One of the key enzymez in anthocyanins biosynthesis pathway is dihydroflavonol 4-reductase which converts dihydroflavonols into their leucoanthocyanidins. In order to investigate the role of 134th amino acid position on substrate specificity determination of dihydroflavonol 4-reductase enzyme، different amino acid sequences of this enzyme have been collected from database and analyzed. Multiple amino acid sequence alignment showed that the amino acid sequence of this enzyme is protected among different species. In two studied species neither of two conserved amino acid including aspargine and aspartic acid at this position was found. Our results clearly indicate that this position cannot alone-responsible for determinate substrate specificity of dihydroflavonol 4-reductase enzyme، and lateral positions of 134th residue maybe are involved in this determining substrate specificity.