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Purification and properties of xanthine dehydrogenase from Streptomyces cyanogenus.
J Biochem. 1979 Jul; 86(1):45-53.JB

Abstract

Xanthine dehydrogenase has been purified to a homogeneous state from cell-free extracts of a strain of Streptomyces. The enzyme has a molecular weight of 125,000 and consists of two subunits with a molecular weight of 67,000. The isoelectric point is at pH 4.4. The enzyme exhibits absorption maxima at 273, 355, and 457 nm and contains FAD, iron, and labile sulfide in a molar ratio of 1 : 7 : 1 per subunit. Little molybdenum could be detected. The enzyme is most active at pH 8.7 and at 40 degrees C, and is stable between pH 7 and 12 (at 4 degrees C for 24 h) and below 55 degrees C (at pH 9 for 10 min). The activity is stimulated by K+ at a concentration of 50 mM or more and also by keeping the enzyme at pH 9 to 11. The activity is inhibited by cyanide, Tiron, and p-chloromercuribenzoate and by adenine and urate. Among the compounds tested, hypoxanthine, guanine, xanthine 2-hydroxypurine, and 6,8-dihydroxypurine are oxidized at considerable rates; hypoxanthine is the best substrate. NAD+ is the preferred electron acceptor. Km values of the enzyme for hypoxanthine, guanine, xanthine, and NAD+ are 0.055, 0.015, 0.15, and 0.11 mM, respectively. Marked differences in the properties of this enzyme compared to others are the activity towards guanine, which has a higher affinity for the enzyme than hypoxanthine and xanthine, and a higher reactivity with hypoxanthine than xanthine. The organism has been identified as Streptomyces cyanogenus.

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

479130

Citation

Ohe, T, and Y Watanabe. "Purification and Properties of Xanthine Dehydrogenase From Streptomyces Cyanogenus." Journal of Biochemistry, vol. 86, no. 1, 1979, pp. 45-53.
Ohe T, Watanabe Y. Purification and properties of xanthine dehydrogenase from Streptomyces cyanogenus. J Biochem. 1979;86(1):45-53.
Ohe, T., & Watanabe, Y. (1979). Purification and properties of xanthine dehydrogenase from Streptomyces cyanogenus. Journal of Biochemistry, 86(1), 45-53.
Ohe T, Watanabe Y. Purification and Properties of Xanthine Dehydrogenase From Streptomyces Cyanogenus. J Biochem. 1979;86(1):45-53. PubMed PMID: 479130.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Purification and properties of xanthine dehydrogenase from Streptomyces cyanogenus. AU - Ohe,T, AU - Watanabe,Y, PY - 1979/7/1/pubmed PY - 1979/7/1/medline PY - 1979/7/1/entrez SP - 45 EP - 53 JF - Journal of biochemistry JO - J Biochem VL - 86 IS - 1 N2 - Xanthine dehydrogenase has been purified to a homogeneous state from cell-free extracts of a strain of Streptomyces. The enzyme has a molecular weight of 125,000 and consists of two subunits with a molecular weight of 67,000. The isoelectric point is at pH 4.4. The enzyme exhibits absorption maxima at 273, 355, and 457 nm and contains FAD, iron, and labile sulfide in a molar ratio of 1 : 7 : 1 per subunit. Little molybdenum could be detected. The enzyme is most active at pH 8.7 and at 40 degrees C, and is stable between pH 7 and 12 (at 4 degrees C for 24 h) and below 55 degrees C (at pH 9 for 10 min). The activity is stimulated by K+ at a concentration of 50 mM or more and also by keeping the enzyme at pH 9 to 11. The activity is inhibited by cyanide, Tiron, and p-chloromercuribenzoate and by adenine and urate. Among the compounds tested, hypoxanthine, guanine, xanthine 2-hydroxypurine, and 6,8-dihydroxypurine are oxidized at considerable rates; hypoxanthine is the best substrate. NAD+ is the preferred electron acceptor. Km values of the enzyme for hypoxanthine, guanine, xanthine, and NAD+ are 0.055, 0.015, 0.15, and 0.11 mM, respectively. Marked differences in the properties of this enzyme compared to others are the activity towards guanine, which has a higher affinity for the enzyme than hypoxanthine and xanthine, and a higher reactivity with hypoxanthine than xanthine. The organism has been identified as Streptomyces cyanogenus. SN - 0021-924X UR - https://www.unboundmedicine.com/medline/citation/479130/Purification_and_properties_of_xanthine_dehydrogenase_from_Streptomyces_cyanogenus_ L2 - https://joi.jlc.jst.go.jp/JST.Journalarchive/biochemistry1922/86.45?lang=en&from=PubMed DB - PRIME DP - Unbound Medicine ER -