Studies of the Catalytically-Active Form of Hypoxanthine-Guanine Phosphoribosyltransferase from Yeast

  • Donald L. Sloan
  • Linda Z. Ali
  • Dian Picou
  • Antonio JosephJr.
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 165)


Studies of the kinetic (1) and structural (2) properties of yeast hypoxanthine-guanine phosphoribosyltransferase (HG-PRTase), an enzyme first purified by Schmidt et al. (3), have been completed recently. This HG-PRTase is composed of two polypeptide subunits(26,000 m.w.), as determined by SDS-gel electrophoresis (2) and catalyzes the synthesis of either IMP or GMP through the use of an ordered Bi Bi kinetic mechanism (1). However, since electro-phoretic studies are conducted at concentrations much higher than those employed during kinetic analyses, the observed dimeric HG-PRTase, may not necessarily be the form of the enzyme responsible for catalysis. In this paper we describe results which suggest the existence of a catalytically-active monomeric HG-PRTase which functions as an enzyme-metal ion complex.


Crosslinking Reagent Manganese Chloride Polypeptide Subunit High Molecular Weight Form Orotate Phosphoribosyltransferase 
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Copyright information

© Springer Science+Business Media New York 1984

Authors and Affiliations

  • Donald L. Sloan
    • 1
  • Linda Z. Ali
    • 1
  • Dian Picou
    • 1
  • Antonio JosephJr.
    • 1
  1. 1.Chemistry Dept.City College of the City University of New YorkNew YorkUSA

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