[NMR paper] 1H-NMR characterization of cucumber peroxidases.

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1H-NMR characterization of cucumber peroxidases.

Related Articles 1H-NMR characterization of cucumber peroxidases.

Biochim Biophys Acta. 1991 Dec 11;1118(1):36-40

Authors: Dugad LB, Goff HM, Abeles FB

Two peroxidase isoenzymes from Cucumber seedlings, one acidic (pI = 4) and one basic (pI = 9), were characterized by 1H-NMR spectroscopy. The NMR spectra were obtained in the native (ferric high-spin) and cyanide ligated (ferric low-spin) forms of both isoenzymes. The NMR spectral comparison of paramagnetically shifted resonances with those of the well characterized horseradish peroxidase C, HRP(C), isoenzyme indicates that both cucumber peroxidases have a protohemin IX prosthetic group with proximal histidine coordinated to the heme iron. The downfield heme 1H-NMR shift pattern is distinct for each isoenzyme, and this reflects presumably dissimilar heme active site environments. The basic isoenzyme shows less asymmetry in heme 1H-NMR signals as compared to the acidic isoenzyme or HRP(C) isoenzyme. It was also found that the acidic cucumber peroxidase exists predominantly as a monomeric species in solution with 30 kDa molecular mass as opposed to its earlier characterization as a 60 kDa dimeric protein.

PMID: 1764475 [PubMed - indexed for MEDLINE]



Source: PubMed