담배 callus (Nicotiana tabacum L. var. Virginia 115)에서 정제한 6-phosphogluconate dehydrogenase에 대한 여러 phenol 화합물의 영향을 조사해 본 결과, chlorogenic acid, esculin과, scopoletin은 모두 이 효소에 대하여 noncompetitive inhibitor로 작용하였으며 $K_i$ 값은 각각 $260;{mu}M$, $230;{mu}M$, $150;{mu}M$이었다. 또한 이 효소는 높은 농도의 caffeic acid와 ferulic acid에 의하여 약간 억제되었으며, 낮은 기질농도에서는 p-coumaric에 의해서도 억제되었다. 그 밖에 erythrose-4-phosphate, indole-3-acetic acid와 aromatic amino acids는 효소의 활성도에 아무런 영향을 미치지 못하였다.
Effect of various phenolic compounds on the activity of tobacco 6-phosphogluconate dehydrogenase were studied. The enzyme was markedly inhibited by chlorogenic acid, esculin, and scopoletin noncompetitively with $K_i$ values of $150;{mu}M$, $230;{mu}M$, and $260;{mu}M$, respectively. The enzyme was also inhibited by caffeic acid and ferulic acid at high effector concentration (0.4 mM) and by p-coumaric acid at low 6-phosphogluconate concentration ($30;{mu}M$). All of the above phenolic compounds are known to be natural components of tobacco plants. Erythrose-4-phosphate, indole-3-acetic acid, and aromatic amino acids did not affect the activity of the enzyme significantly.
