Analysis of repeating oligonucleotide sequences in ribonucleic acids using an Apple II microcomputer

A simple computer program has been developed to locate repeatingsubsequences of all possible lengths in a given nucleic acid.The observed number of repeats of subsequences was comparedwith the expected number of such repeats in several RNAs. Theanalysis showed that, in the case of rRNAs, there are no constraintsin the choice of the fourth and the higher order nucleotides,while the selection is maximum at the level of nearest neighbour.This is, however, not true for RNAs coding for proteins, wherethe constraints are also found at the level of nucleotides containingfive or more bases. Received on November 15, 1985; accepted on April 1, 1986     

Reduction by a model of NAD(P)H: XXIII. Kinetics for the reduction of 2-acylpyridines

Kinetics for the reduction of 2-acetylpyridine and 2-benzoylpyridine with 1-benzyl-1,4-dihydronicotinamide in acetonitrile has been studied. Isotope effects of the reduction reveal that the transfer of hydrogen nucleus is involved in the rate-determining step. The effect of zinc ion on the reaction rate has been studied quantitatively and the true reacting species have been elucidated.