Differential effects of deoxyribonucleotides on respiration of virulent pneumococci.

Firshein, William (Wesleyan University, Middletown, Conn.), Robert J. Erickson, and Bernadette A. Gargan. Differential effects of deoxyribonucleotides on respiration of virulent pneumococci. J. Bacteriol. 92:1645-1654. 1966.-Four naturally occurring deoxyribonucleotides affect respiration in three virulent pneumococcal types (Diplococcus pneumoniae) differentially. Deoxyadenylic acid (dAMP) stimulates respiration in type I and slightly stimulates respiration in type III, but has no effect in type II. Deoxyguanylic acid (dGMP) stimulates respiration in type I, inhibits respiration in type II, and has no effect in type III. Thymidylic acid (dTMP) inhibits respiration of type I, but is stimulatory in types II and III. Deoxycytidylic acid (dCMP) inhibits respiration of all three pneumococcal types. Of a large number of related compounds, including many of the naturally occurring deoxynucleosides, nucleosides, nucleotides, purines, and pyrimidines, thymidine is slightly effective in types II and III, and deoxycytidine is slightly inhibitory in all three types. None of the remaining compounds affects respiration significantly. With a few exceptions, there is a correlation between the extent of uptake of each deoxynucleotide in the three types and their ability to stimulate (or inhibit) respiration. The greater the uptake, the greater the enhancement of respiration. The less uptake, the greater the inhibition of respiration. In cell-free extracts of type I, dAMP also stimulates the oxidative decarboxylation of pyruvic acid. During this reaction, dAMP is phosphorylated to deoxyadenosine diphosphate (dADP) and to deoxyadenosine triphosphate (dATP).