The isomerization of glutamate dehydrogenase in response to lead toxicity in maize

Document Type

Article

Publication Title

Biologia Plantarum

Abstract

Maize (Zea mays] was cultivated on lead-adultrated soil up to 600 mg(Pb) kg-1. At maturity, the maize seeds were harvested. The glutamate dehydrogenise (GDH) was fractionated to its isoenzyme population by Rotofor isoelectric focusing (IEF). The increasing Pb concentration progressively enhanced the more acidic isoenzymes (pI 6.3 - 6.5), and at the same time suppressed the less acidic isoenzymes (pI 7.3 - 7.8) and at the 600 mg(Pb) kg-1(soil) only the most acidic couple of isoenzymes (pI 6.3, and 6.5) were detectable. The NH4+ Km values of the GDH increased progressively from 6.2 in the control to 100 mM and the total glutathione content of maize seeds from 60 to 240 nmol g-1 in the 600 mg(Pb) kg-1(soil) treated maize. The orderly, and sequential isomerization of GDH in response to Pb suggests that the enzyme functions as a sensor in the monitoring of environmentally induced stress.

First Page

389

Last Page

398

DOI

10.1023/A:1001018014681

Publication Date

1-1-1997

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