Enzymes activity of phenylpropanoid pathway in red flesh apples

Red flesh apples have the distinction of anthocyanin pigment possessing in the flesh fruit. Anthocyanin pigments protect human cells against oxidative damage. They may also offer anti-cancer, anti-inflammatory and anti-viral properties. Anthocyanin synthesis occurs during the phenylpropanoid pathway in apples. This study was conducted aimed to assay the specific activities of phenylpropanoid pathway enzymes in red flesh apples. A factorial experiment with three factors was performed in a randomized complete block design (RCBD) with 3 replicates. Factors included genotypes of apples (5 red flesh apples and 3 white flesh apples) and parts of the plant (leaves, flesh, and whole fruit (including skin, flesh, and seeds)) and 3 sampling dates. The activity of phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), dihydro flavonol 4 reductase (DFR), Flavanvn 3-hydroxylase (F3-H or FHT), and flavonol synthase (FLS) were measured according to nkat (nano mol s^‑1) kg^‑1 protein. Based on the obtained results, the pattern of specific activity of the enzymes was variable in different parts of the fruit, different genotypes, and dates. However, it was observed that PAL in leaf, CHS and DFR in flesh, and CHS and FLS in whole fruit presented a higher activity. In the second sampling time, the enzyme activity was much higher. In total, the enzyme activity and changes in enzymatic activity among genotypes showed a significant difference that this difference seemed to be due to genetic variation of apple genotypes.