S-adenosylhomocysteine hydrolase from the thermophilic archaeon Sulfolobus solfataricus: purification, physico-chemical and immunological properties.
S-Adenosylhomocysteine hydrolase from Sulfolobus solfataricus, a thermoacidophilic archaeon optimally growing at 87 degrees C, has been purified to homogeneity. The specific activity of the homogeneous enzyme is 161 nmol of S-adenosylhomocysteine formed per min per mg of protein, and the overall yield, by immunoaffinity purification, is 51%. The enzyme has a molecular mass of 190 kDa, is composed of four identical subunits (subunit mass 47 kDa), and contains four molecules of tightly-bound NAD+ per tetramer of which about 40% is in the reduced form. Physico-chemical features, including amino-acid composition and secondary structure, are reported. The pure protein, used to raise specific rabbit antisera, shows immunological properties different from other S-adenosylhomocysteine-metabolizing enzymes. The enzyme is thermophilic with an optimum temperature of 75 degrees C, and shows an apparent melting temperature of 95 degrees C by measuring its residual activity after 10 min incubation at increasing temperatures.
Porcelli
M
M
Institute of Biochemistry of Macromolecules, Medical School, Second University of Naples, Italy.
Cacciapuoti
G
G
Fusco
S
S
Iacomino
G
G
Gambacorta
A
A
De Rosa
M
M
Zappia
V
V
D043383:Adenosylhomocysteinase; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004795:Enzyme Stability; D006358:Hot Temperature; D006867:Hydrolases / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D007106:Immune Sera / Q000276:immunology; D009243:NAD / Q000032:analysis; D017433:Protein Structure, Secondary; D011817:Rabbits; D016944:Sulfolobus / Q000201:enzymology*
D000596:Amino Acids; D007106:Immune Sera; D009243:NAD; D006867:Hydrolases; D043383:Adenosylhomocysteinase