Exploring redox modulation of plant UDP-glucose pyrophosphorylase

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Názov: Exploring redox modulation of plant UDP-glucose pyrophosphorylase
Autori: Decker, Daniel, 1986, Aubert, Juliette, Wilczynska, Malgorzata, Kleczkowski, Leszek A., 1954
Zdroj: International Journal of Molecular Sciences. 24(10)
Predmety: carbohydrate metabolism, glutathione, hydrogen peroxide, protein structure, redox regulation, substrate affinity, UDP-glucose pyrophosphorylase
Popis: UDP-glucose (UDPG) pyrophosphorylase (UGPase) catalyzes a reversible reaction, producing UDPG, which serves as an essential precursor for hundreds of glycosyltransferases in all organisms. In this study, activities of purified UGPases from sugarcane and barley were found to be reversibly redox modulated in vitro through oxidation by hydrogen peroxide or oxidized glutathione (GSSG) and through reduction by dithiothreitol or glutathione. Generally, while oxidative treatment decreased UGPase activity, a subsequent reduction restored the activity. The oxidized enzyme had increased Km values with substrates, especially pyrophosphate. The increased Km values were also observed, regardless of redox status, for UGPase cysteine mutants (Cys102Ser and Cys99Ser for sugarcane and barley UGPases, respectively). However, activities and substrate affinities (Kms) of sugarcane Cys102Ser mutant, but not barley Cys99Ser, were still prone to redox modulation. The data suggest that plant UGPase is subject to redox control primarily via changes in the redox status of a single cysteine. Other cysteines may also, to some extent, contribute to UGPase redox status, as seen for sugarcane enzymes. The results are discussed with respect to earlier reported details of redox modulation of eukaryotic UGPases and regarding the structure/function properties of these proteins.
Popis súboru: electronic
Prístupová URL adresa: https://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-209182
https://doi.org/10.3390/ijms24108914
Databáza: SwePub
Popis
Abstrakt:UDP-glucose (UDPG) pyrophosphorylase (UGPase) catalyzes a reversible reaction, producing UDPG, which serves as an essential precursor for hundreds of glycosyltransferases in all organisms. In this study, activities of purified UGPases from sugarcane and barley were found to be reversibly redox modulated in vitro through oxidation by hydrogen peroxide or oxidized glutathione (GSSG) and through reduction by dithiothreitol or glutathione. Generally, while oxidative treatment decreased UGPase activity, a subsequent reduction restored the activity. The oxidized enzyme had increased Km values with substrates, especially pyrophosphate. The increased Km values were also observed, regardless of redox status, for UGPase cysteine mutants (Cys102Ser and Cys99Ser for sugarcane and barley UGPases, respectively). However, activities and substrate affinities (Kms) of sugarcane Cys102Ser mutant, but not barley Cys99Ser, were still prone to redox modulation. The data suggest that plant UGPase is subject to redox control primarily via changes in the redox status of a single cysteine. Other cysteines may also, to some extent, contribute to UGPase redox status, as seen for sugarcane enzymes. The results are discussed with respect to earlier reported details of redox modulation of eukaryotic UGPases and regarding the structure/function properties of these proteins.
ISSN:16616596
14220067
DOI:10.3390/ijms24108914