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Optical and electron paramagnetic resonance spectroscopic studies on purine hydroxylase II from Aspergillus nidulans.
Arch Biochem Biophys. 1984 Mar; 229(2):596-603.AB

Abstract

Purine hydroxylase II from Aspergillus nidulans contains a molybdenum cofactor very similar to that found in a number of other molybdenum-containing hydroxylases. (A. nidulans contains two purine hydroxylases, I and II, related to each other by possession of a common cofactor and overlapping substrate specificity.) Addition of reducing substrates effects bleaching of the visible absorption spectrum of the enzyme, the decrease in absorbance at 450 nm being linearly proportional to that at 550 nm. No increase in absorption at longer wavelengths was observed during such titrations. Electron paramagnetic resonance studies of reduced samples of native and modified enzyme species showed the presence of a number of Mo(V) signals (gav = 1.97), exhibiting H hyperfine coupling, comparable to those in the corresponding enzymes from other sources. The enzyme possesses two non-heme-iron-sulfur centers, one (Fe2S2)I with gav less than 2.0 and the other (Fe2S2)II with gav greater than 2.0. The flavin radical signal observed at pH 7.8 had a linewidth of 1.5 mT, indicating it to be the anionic form FAD- . In this respect purine hydroxylase II is unique among all molybdenum-containing hydroxylases studied to date.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

6322698

Citation

Coughlan, M P., et al. "Optical and Electron Paramagnetic Resonance Spectroscopic Studies On Purine Hydroxylase II From Aspergillus Nidulans." Archives of Biochemistry and Biophysics, vol. 229, no. 2, 1984, pp. 596-603.
Coughlan MP, Mehra RK, Barber MJ, et al. Optical and electron paramagnetic resonance spectroscopic studies on purine hydroxylase II from Aspergillus nidulans. Arch Biochem Biophys. 1984;229(2):596-603.
Coughlan, M. P., Mehra, R. K., Barber, M. J., & Siegel, L. M. (1984). Optical and electron paramagnetic resonance spectroscopic studies on purine hydroxylase II from Aspergillus nidulans. Archives of Biochemistry and Biophysics, 229(2), 596-603.
Coughlan MP, et al. Optical and Electron Paramagnetic Resonance Spectroscopic Studies On Purine Hydroxylase II From Aspergillus Nidulans. Arch Biochem Biophys. 1984;229(2):596-603. PubMed PMID: 6322698.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optical and electron paramagnetic resonance spectroscopic studies on purine hydroxylase II from Aspergillus nidulans. AU - Coughlan,M P, AU - Mehra,R K, AU - Barber,M J, AU - Siegel,L M, PY - 1984/3/1/pubmed PY - 1984/3/1/medline PY - 1984/3/1/entrez SP - 596 EP - 603 JF - Archives of biochemistry and biophysics JO - Arch Biochem Biophys VL - 229 IS - 2 N2 - Purine hydroxylase II from Aspergillus nidulans contains a molybdenum cofactor very similar to that found in a number of other molybdenum-containing hydroxylases. (A. nidulans contains two purine hydroxylases, I and II, related to each other by possession of a common cofactor and overlapping substrate specificity.) Addition of reducing substrates effects bleaching of the visible absorption spectrum of the enzyme, the decrease in absorbance at 450 nm being linearly proportional to that at 550 nm. No increase in absorption at longer wavelengths was observed during such titrations. Electron paramagnetic resonance studies of reduced samples of native and modified enzyme species showed the presence of a number of Mo(V) signals (gav = 1.97), exhibiting H hyperfine coupling, comparable to those in the corresponding enzymes from other sources. The enzyme possesses two non-heme-iron-sulfur centers, one (Fe2S2)I with gav less than 2.0 and the other (Fe2S2)II with gav greater than 2.0. The flavin radical signal observed at pH 7.8 had a linewidth of 1.5 mT, indicating it to be the anionic form FAD- . In this respect purine hydroxylase II is unique among all molybdenum-containing hydroxylases studied to date. SN - 0003-9861 UR - https://www.unboundmedicine.com/medline/citation/6322698/Optical_and_electron_paramagnetic_resonance_spectroscopic_studies_on_purine_hydroxylase_II_from_Aspergillus_nidulans_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0003-9861(84)90192-9 DB - PRIME DP - Unbound Medicine ER -