Cell Biological Studies on Growth and Development Effect of polyamine and $Ca^{2+}$ on D-glucose-6-phosphate cyclohydrolase activity in carrot root protoplast

생체생장에 관한 세포생물학적 연구 당근 뿌리의 원형질체에서 D-glucose-6-phosphate cyclohydrolase 활성도에 미치는 polyamine과 $Ca^{2+}$의 영향

The effect of polyamine and Ca2+ on D-glucose-6-phosphate cyclohydrolase activity was studied in Daucus carota root. The enzyme activity was reduced in response to increase in concentration of Ca2+, not the Ca2+-calmodulin complex. The inhibition effect due to Ca2+ was reversed by polyamine, especially remarkable at low concentration of Ca2+. The effect of the Ca2+ on the enzyme seemed to compete with polyamine according to the Lineweaver-Burk plot. The enzyme activity from carrot root protoplast cultured in the prescence of verapamil was higher than that of the control. Such cumulative results suggest that the inhibition by the Ca2+ and enhancement or reversal by polyamine could regulate the biosynthesis of pectin and hemicellulose to some extent.