Evidence for essential histidine and dicarboxylic amino-acid residues in the active site of UDP-glucose : solasodine glucosyltransferase from eggplant leaves.

Paulina Nawłoka; Małgorzata Kalinowska; Cezary Paczkowski; Zdzisław A Wojciechowski

doi:10.18388/abp.2003_3710

Evidence for essential histidine and dicarboxylic amino-acid residues in the active site of UDP-glucose : solasodine glucosyltransferase from eggplant leaves.

Paulina Nawłoka Institute of Biochemistry, Warsaw University, I. Miecznikowa 1, 02-096 Warsaw, Poland.;
Małgorzata Kalinowska
Cezary Paczkowski
Zdzisław A Wojciechowski

DOI: https://doi.org/10.18388/abp.2003_3710

Abstract

Effects of several chemical probes selectively modifying various amino-acid residues on the activity of UDP-glucose : solasodine glucosyltransferase from eggplant leaves was studied. It was shown that diethylpyrocarbonate (DEPC), a specific modifier of histidine residues, was strongly inhibitory. However, in the presence of excessive amounts of the enzyme substrates, i.e. either UDP-glucose or solasodine, the inhibitory effect of DEPC was much weaker indicating that histidine (or histidines) are present in the active site of the enzyme. Our results suggest also that unmodified residues of glutamic (or aspartic) acid, lysine, cysteine, tyrosine and tryptophan are necessary for full activity of the enzyme. Reagents modifying serine and arginine residues have no effect on the enzyme activity.

Published

2003-06-30

Issue

Vol. 50 No. 2 (2003)

Section

Articles

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