Buckwheat Hypocotyls Research Articles

α-aminooxy-β-phenylpropionic acid — a potent inhibitor of L-phenylalanine ammonia-lyase in vitro and in vivo

The hydroxylamine analogue of phenylalanine — α-aminooxy-β-phenyl-propionic acid — is a potent inhibitor of phenylalanine ammonia-lyases (PAL) of both higher plant and fungal origin. The inhibition is competitive, and K i values were found to be 1.4 nM for the enzyme from buckwheat and 55 nM for the enzyme from the yeast Rhodotorula glutinis. Evidence is presented that the analogue inhibits phenylalanine ammonia-lyase in vivo in buckwheat hypocotyls.

Induction by light of hydroxy-cinnamoyl-CoA-quinate-transferase activity in buckwheat hypocotyls.

Induction by light of hydroxy-cinnamoyl-CoA-quinate-transferase activity in buckwheat hypocotyls.

The estimation of phenylalanine ammonia-lyase (PAL)-activity in intact cells of higher plant tissue

A procedure is described which permits the estimation of the relative activity of phenylalanine ammonia-lyase (E.C. 4.3.1.5.) in intact plant cells, exemplified by buckwheat hypocotyls. Hypocotyl segments are incubated at pH 5.5 with L-[3-(3)H]phenylalanine. N(3)HH2, which is liberated from phenylalanine by the action of phenylalanine ammonia-lyase, equilibrates with tissue water to yield (3)HOH, which is recovered by sublimation. Participation of phenylalanine transaminase in the reactions leading to (3)HOH formation is excluded, and it is conclusively shown that (3)HOH is formed intracellularly and not by enzymatic activity leaking out of wounded tissue.

Concomitant induction of phenylalanine ammonia-lyase and cinnamic acid 4-hydroxylase during illumination of excised buckwheat hypocotyls

Concomitant induction of phenylalanine ammonia-lyase and cinnamic acid 4-hydroxylase during illumination of excised buckwheat hypocotyls

Das auftreten des “NIH-shifts” bei der in vivo und in vitro bildung hydroxylierter zimtsäurederivate in buchweizenhypokotylen ( Fagopyrum esculentum)

4- 3H-cinnamic acid (U- 14C) was supplied to segments of buckwheat hypocotyls during temporary illumination. Retention of tritium was determined in the following compounds: rutin (46·5 per cent), chlorogenic acid (50 per cent), cyanidin (40 per cent) and leucocyanidin (32 per cent). When 4- 3H-cinnamic acid (U- 14C) was converted to p-coumaric acid by a microsome preparation from buckwheat hypocotyls, 88 per cent retention of tritium was found in the reaction product.