title: [5'-methylthioadenosine phosphorylase from Caldariella acidophila. 1. Purification and partial characterization].
abstract: 5'-Methylthioadenosine phosphorylase has been isolated from C.acidophila, a thermophilic bacterium living in acid hot springs at temperatures ranging from 63 to 89 degrees C. The enzyme has been purified to homogeneity in 32% yield. The enzyme shows a high degree of thermophilicity, its temperature optimum being 93 degrees C in the in vitro assay. The enzyme is exceptionally stable; no loss of activity was observable after exposure for 1 h at 100 degrees C. The optimum pH is about 7,2, with one-half of the maximal activity occurring at pH 6 and 9. The apparent Km for the substrates are: 8,3 x 10(-5) M for MTA and 4,3 x 10(-4) M for phosphate ions.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives; D001419:Bacteria / Q000201:enzymology*; D011232:Chemical Precipitation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007700:Kinetics; D010430:Pentosyltransferases / Q000302:isolation & purification*; D011683:Purine-Nucleoside Phosphorylase / Q000302:isolation & purification*; D013872:Thionucleosides
chemical_list: D007202:Indicators and Reagents; D013872:Thionucleosides; D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; C021784:5'-methylthioadenosine phosphorylase; D000241:Adenosine
vernacular_title: 5'-metiltioadenosina fosforilasi da Caldariella acidophila. 1 - Purificazione e parziale caratterizzazione.