ADENOSINE TRIPHOSPHATASE ACTIVITY IN HEVEA LATE! WITH SPECIAL REfERENCE TO BROWN BAST

Abstract

Attached

Adenosine triphosphatase (ATP-ase) from F-serum of Hevea brasiliensis was purified by (NH4)2S04 sequential precipitation, gel filtration and gel electrophoretic techniques. This enzyme had a pH optimum of 7.5 and a temperature optimum of 37°C. It had a Km value in the range of 0.6 to 0.8 mM at pH 7.4 and 37°C in Tris/HCl buffer. The activity of the enzyme was found to be cation dependent. The removal of cations by dialysis and re-introduction them into the enzyme system confirmed this. Five cationl were inve.tigated for their effect on the ATP-ase activity and the stimulatory action walSin the order of => K) Kg;> Ca) Na. When various cationic combinations two-ion, three-ion and four-ion etc was tried, it was observed that combinations (Na + K), (Na + K + Mn), (Ca + Mg + K + Mn) had greater stimulatory influence on the enzyme activity. comparative ~tudies on ATP-ase activity in brown bast and healthy trees of Hevea"showed higherATP-alSeactivity in healthy &erum of clones RRIM 600 and RRIC 52 J than that of brown bast trees and!!!! versa in the clones of PB 86 and RRIC 101. In brown bast bark the enzyme activity was always found to be

~reater th~n that of healthy i~ all four clonea inveatigated namely RRIM 600, RRIC 101, RRlC 52 and PB 80. The ATP-ase activity in bark extracts at different height. of brown ba5t trees was found to be higher than that of healthy trees, at corresponding heights, giving an indication of the spread of brown bast condition into the neighbouring tissues too, as 5uggested by some of the previoua workers. cationic analysis of bark and latex &howed Ca-lees, Mg~ore (except for RRIM 600), N-more were associated with brown bast condition. When these conditions were Simulated, a higher ATP-ase activity as anticipated, was observed in F-serum. These result& strongly favours a generally held view that a nutritional imbalance· may be a.sociated with this physiological disorder. In addition to various cations and their combinations, phenolic substances in the bark also had a significant effect on ATP-ase activity. Kaemperol was found to be stimulatory at low concentrations (up to 4 mM) and had an inhibitory effect at high concentrations. 2.4 Dinitrophenol and Quercetin were inhibitory at low concentrations (up to 1 mM and 8 roM respectively) and they were found to

be stimulatory at above these concentrations.