title: Studies of the 2':3'-cyclic nucleotide phosphodiesterase of Haemophilus influenzae.
abstract: The 2':3'-cyclic nucleotide phosphodiesterase:3'-nucleotidase of Haemophilus influenzae was purified from a periplasmic preparation by affinity chromatographic techniques. The enzyme-catalysed hydrolysis of 2':3'-cyclic AMP to adenosine without accumulation of the intermediate substrate 3'-AMP was demonstrated by high performance liquid chromatography. Competitive inhibition of the enzyme by a variety of nucleosides and mononucleotides indicated the presence of either purine or pyrimidine bases to be essential for selective interactions with the enzyme, and confirmed the need for a 3'-position phosphate for the functioning of mononucleotides as substrates for the enzyme. The enzyme had a molecular weight of 79 000, was stable at low temperatures and was thermally denatured at temperatures above 50 degrees C.
mesh_terms: D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000378:metabolism*; D001667:Binding, Competitive; D002851:Chromatography, High Pressure Liquid; D004791:Enzyme Inhibitors; D006193:Haemophilus influenzae / Q000201:enzymology*; D006358:Hot Temperature; D007700:Kinetics; D008970:Molecular Weight; D011489:Protein Denaturation; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases