Soluble 5'-nucleotidase from thyroid gland partial purification and properties.

A soluble 5'-nucleotidase from pig thyroid was purified over 110-fold by chromatography on phosphocellulose, (NH4)2SO4 precipitation and gel filtration on Sephadex G-150. The purified 5-nucleotidase was free of non-specific phosphatases. The enzyme had optimum pH at 6.5 and hydrolysed preferentially IMP and GMP. The Km values were 0.66 and 1.0 mM for IMP and GMP, respectively. The enzyme also hydrolysed other nucleotides and showed the following relative Vmax:IMP>CMP>AMP>UMP.Mg2+ was necessary for the enzyme activity.