title: 3-Ribosyl-6-methyluracil as a phosphate acceptor in the synthesis of the internucleotide bond catalyzed by pancreatic ribonuclease.
abstract: The synthesis of uridylyl-(3'-5')-3-ribosyl-6-methyluracil (UprmU) catalyzed by pancreatic ribonuclease (EC 3.4.1.22) has been performed using uridine 2', 3'-cyclic phosphate (U greater than p) as phosphate donor and 3-ribosyl-6-methyluracil (rmU) as phosphate acceptor. The rate of synthesis of UprmU is much higher than that of uridylyl-(3'-5')-uridine (UpU) in a control experiment under the same conditions with uridine as acceptor. The yields of UpU and UprmU were 20 and 17% respectively. The competitive hydrolysis of the initial U greater than p also proceeds faster when rmU is used as the acceptor. The relationship between the conformation of this nucleoside and its acceptor activity in the enzymatic synthesis of the internucleotide bond is discussed.
mesh_terms: D007700:Kinetics; D009841:Oligonucleotides / Q000096:biosynthesis*; D009843:Oligoribonucleotides / Q000096:biosynthesis*; D010179:Pancreas / Q000201:enzymology; D012260:Ribonucleases / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D014529:Uridine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D009841:Oligonucleotides; D009843:Oligoribonucleotides; D012260:Ribonucleases; D014529:Uridine