Characterization and expression of phenylalanine hydroxylase in rabbits under different feeding conditions of faba bean (Vicia faba L.)

Abstract

Phenylalanine hydroxylase (PAH) enzyme plays a key role in dopamine biosynthesis in humans, rabbits, and most mammals. Rabbits, as an ideal model, were used to study the expression of the PAH gene under different feeding conditions of faba bean (Vicia faba L., Sakha 3). PAH genes (≈1,400 bp) in control and faba beanfed rabbits were PCR amplified, sequenced, and aligned with the reference gene (acc. no. 013672). The first 320 pb of PAH sequences representing the N-terminal of the gene was almost identical. High genetic similarity values were detected in PAH gene sequences for both control and faba bean-fed rabbits with the reference gene (99.80%). The results indicated very little sequence variations, which have no effect on the enzyme activity in both control and faba bean-fed rabbits. Real Time quantitative Polymerase Chain Reaction (RT-qPCR) analysis showed that the PAH gene was overexpressed after feeding on dry faba bean form compared with feeding on the fresh form. Furthermore, Western blotting results reflected superior PAH protein due to the direct influence of feeding on dry faba bean. In conclusion, our findings indicated the direct effect of fresh and dry faba bean diet on increasing phenylalanine amino acid in rabbits' blood, which consequently increases the expression of PAH gene, thus improving the quality of life for humans.