Optimization of invertase assay conditions in rubber tree plants (Hevea brasiliensis Muell. Arg.)

Daria Pimenta De Oliveira,Nelson Delú Filho,Luiz Edson Mota De Oliveira

doi:10.1590/s0100-67622006000500001

Daria Pimenta De Oliveira, Nelson Delú Filho + Show 1 more

Open Access

https://doi.org/10.1590/s0100-67622006000500001

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Journal: Revista Árvore	Publication Date: Oct 1, 2006
Citations: 9	License type: cc-by

Affiliation: Universidade Vale do Rio Verde

Abstract

The objective of this work was to define the optimal conditions for invertase assay, seeking to determine the ideal parameters for the different isoenzymes of leaf and bark tissues in adult rubber trees. Assays of varying pH, sucrose concentration and temperature of the reaction medium were conducted for the two investigated isoenzymes. The results pointed out the existence of two different pH related isoforms for the two analyzed tissues, with an isoenzyme being more active at pH 5,5 and the other at neutral/alkaline pH. Leaf blade isoenzymes presented similar values for substrate concentration, whereas the bark isoenzyme presented maximum values below those previously reported. The assays at different temperatures presented similar values for leaf isoenzymes, though they have differed significantly among the obtained values.

Highlights

Invertase acts upon the catalysis of sucrose irreversible hydrolysis producing both fructose and glucose
Acid invertases are located inside the vacuole and the cell wall (KRISHNAN et al, 1984; SALZER and HAGER, 1993), whilst neutral or alkaline invertases occur in the cytosol of plant cells (STURN and CHRISPEELS, 1990)
It has been proposed that soluble invertases take part in the regulation of hexose levels in mature leaves (RICARDO, 1974; RICARDO and SOVIA, 1974) and fruits (LINGLE and DUNLOP, 1987), and in the mobilization of sucrose stored in the vacuoles, being responsible for the regulation of cell turgescence (LEIGH et al, 1979)

Summary

Introduction

Invertase acts upon the catalysis of sucrose irreversible hydrolysis producing both fructose and glucose. Invertases can be classified according to their subcellular localization, their ideal pH of activity and respective isoelectric points (AVIGAD, 1982). Acid invertases are located inside the vacuole and the cell wall (KRISHNAN et al, 1984; SALZER and HAGER, 1993), whilst neutral or alkaline invertases occur in the cytosol of plant cells (STURN and CHRISPEELS, 1990). Another classification takes into account the solubility of the different isoenzymes present in the cell.

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