@article { author = {HAGHIGHI, B. and FALAHATI, F.}, title = {INVOLVEMENT OF ESSENTIAL LYSINE RESIDUES IN THE CATALYTIC ACTIVITY OF GLUCOSE 6-PHOSPHATE DEHYROGENASE PURIFIED FROM STREPTOMYCES AUREOFACIENS}, journal = {Iranian Journal of Science}, volume = {31}, number = {3}, pages = {313-320}, year = {2007}, publisher = {Springer}, issn = {2731-8095}, eissn = {2731-8109}, doi = {10.22099/ijsts.2007.2370}, abstract = {Glucose 6- phosphate dehydrogenase from streptomyces aureofaciens was purified andinactivated by pyridoxal 5′-phosphate (PLP). The inactivation was a pseudo-first order and time-dependentreaction. Complete inactivation was achieved at 0.2mM PLP within 16 minutes. The type of inhibition wascompetitive with respect to Glucose 6- phosphate. Spectral characteristics of PLP-enzyme complexcorresponded to the formation of a Schiff’s base between PLP and lysine residue(s) of the enzyme. Intrinsicprotein fluorescence sharply decreased upon PLP modification with about a 10 nm red shift. The presence ofglucose 6-phosphate in the incubation mixture prevented the fluorescence change. Fluorescence studiesrevealed that NAD+ and NADP+ binding induces different conformational changes in pyridoxylated enzyme.The stochiometry of PLP binding to the enzyme showed that 2 moles of lysine residues were modified permole of enzyme. The data indicated that the modified lysine residues are involved in substrate binding and/orcatalytic activity of this enzyme.}, keywords = {Glucose 6-phosphate dehydrogenase,pyridoxal 5’-phosphate,essential lysine residue}, url = {https://ijsts.shirazu.ac.ir/article_2370.html}, eprint = {https://ijsts.shirazu.ac.ir/article_2370_f25133d37949f7dcabe5aa464f0b8925.pdf} }