6533b7d1fe1ef96bd125cb53

RESEARCH PRODUCT

Die Glucose-Oxydasen aus Penicillium notatum (Notatin) und Aspergillus niger (Nigerin) I. Isolierung und einige molekulare eigenschaften

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Summary By chromatography on carboxymethyl- and diethylaminoethyl-Sephadex pure preparations of the glucose oxidases ( β - d -glucose: oxygen oxidoreductase, EC 1.1.3.4) notatin from Penicillium notatum and nigerin from Aspergillus niger could be obtained. Differences in the binding to the cation- and anion-exchangers indicate that these two glucose oxidases differ markedly with respect to the structures of the respective apoenzymes. A mixture of notatin and nigerin can easily be separated by chromatography. Moreover, there are also structural differences in the neighbourhood of the prosthetic flavin-adenine dinucleotide groups. The flavin-adenine dinucleotide spectrum of notatin is shifted to greater wavelength by about 4 m μ , compared with that of nigerin. The molecular constants of sedimentation and diffusion are very similar. The molecular weight of notatin was found to be 142 000 and that of nigerin to be 151 000. Differences in the partial specific volumes were also established: 0.727 cm 3 ·g −1 for notatin and 0.711 cm 3 · g −1 for nigerin. Both of these glucose oxidases possess 2.2 flavin groups per molecule, as can be concluded from spectroscopic data and molecular weights. The flavin contents of certain other apparently pure preparations of nigerin obtained from other crude samples from the same source were lower by up to 20%.