Clostridial Purification

Another study (Self and Stadtman 2000) described the purification of XDH from C. purinolyticum, a purine-fermenting strain originally isolated as an adenine-fermentor (Dtirre et al. 1981). Selenium was labile (cyanolyzable) and required for XDH activity. Similar to XDH from E. barkeri, XDH from C. purinolyticum consisted of three subunits (determined by SDS-PAGE). However, XDH from C. purinolyticum was significantly stable when isolated under aerobic conditions. Although these reports solidify the previously speculative data that selenium is present as a labile cofactor in clostridial XDH, the exact nature of selenium and the molecules to which... 

Cone JE, del Rio RM, Stadtman TC. 1977. Clostridial glycine reductase complex. Purification and characterization of the selenoprotein component. J Biol Chem 252 5337 4. 

Tanaka H, Stadtman TC. 1979. Selenium-dependent clostridial glycine reductase. Purification and characterization of the two membrane-associated protein components. J Biol Chem 254 447-52. 

Turner DC, Stadtman TC. 1973. Purification of protein components of the clostridial glycine reductase system and characterization of protein A as a selenoprotein. Arch Biochem Biophys 154 366-81. 

Nair and Garcia (122) extract bile acids from serum (adjusted to pH 11) with ethanol. The dried extract is partitioned between an alkaline aqueous phase and diethyl ether and the remaining lower phase is subjected to clostridial cholyl glycine hydrolase at pH 5.6. After further acidification free bile acids are extracted with ether. The subsequent purification procedure is similar to that above (31), and a triple component (QF-1/SE-30/NGS) column (see Table XIll) is used for quantitative analysis. With the omission of the diethyl ether extraction of the alkaline aqueous phase the same procedure was used with rat bile. 

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