Limited hydrolysis of tRNA by phosphodiesterase.
Digestion of tRNA by electrophoretically pure phosphodiesterase is limited to a short sequence of nucleotides at the 3'-terminus. On the average, four percent of all nucleotides can be released from tRNA. The optimum Mg2 concentration is 10mM and the optimum pH 9.2. The mode of action is a random attack by the enzyme on the substrate. The terminal AMP is completely removed at 15 degrees C after short incubation; about 400 mol of AMP were removed per min by 1 mol of enzyme. The following CMP residues are released much more slowly; at 15 degrees C incompletely, and at 37 degrees C more or less completely in 1 h. In about 50% of the tRNA molecules, the fourth nucleotide could be removed in very long incubations or with very high enzyme concentrations.
D000249:Adenosine Monophosphate / Q000378:metabolism; D001483:Base Sequence; D003568:Cytidine Monophosphate / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008274:Magnesium / Q000494:pharmacology; D009713:Nucleotidyltransferases / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*
D000249:Adenosine Monophosphate; D012343:RNA, Transfer; D009713:Nucleotidyltransferases; D010727:Phosphoric Diester Hydrolases; D003568:Cytidine Monophosphate; D008274:Magnesium