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Improving of cephalotaxine production in Cephalotaxus mannii suspension cultures by alanine and its derivatives

Li, Yong-Cheng, Jiang, Xuan-Xian
Plant cell, tissue, and organ culture 2019 v.136 no.1 pp. 101-108
Cephalotaxus mannii, alanine, biosynthesis, glucose 6-phosphate, metabolites, pentose phosphate cycle, pyruvate kinase, pyruvic acid
The effects of L-alanine and its derivatives on cephalotaxine production of Cephalotaxus mannii suspension cultures were investigated in this paper. L-alanine, L-cyclohexylalanine and D-alanine, respectively were added to the suspension cultures of C. mannii cell at day 15 of cultivation. The cultures treated with L-cyclohexylalanine showed the highest cephalotaxine yield in all treated cultures. The yield of cephalotaxine obtained reached 5.21 mg L⁻¹, 7.03 mg L⁻¹ and 4.85 mg L⁻¹, respectively, while treated with the optimal concentrations of L-alanine, L-cyclohexylalanine and D-alanine, which were 1.8, 2.5 and 1.7 times that of the control cultures (2.85 mg L⁻¹). To gain better understanding of their effect mechanisms on cephalotaxine production, some key enzymes and intermediate metabolites in metabolic pathway were analyzed. It was found that the activity of pyruvate kinase (PK) was inhibited and the content of pyruvic acid in cells decreased simultaneously in all treatment cells. The activity of PK was decreased by 44% and the content of pyruvic acid was reduced by 31% in the cells treated with L-cyclohexylalanine compared with the controls. Conversely, the activity of glucose-6-phosphate dehydrogenase of pentose phosphate pathway (HMP) was increased after adding L-alanine and its derivatives to the cultures. Based on the experimental results, it may be inferred that enhancing the flux of HMP with alanine and its derivatives benefits the biosynthesis of cephalotaxine.