A guanosine 3′,5′-bis(diphosphate) (ppGpp) and guanosine 3′-diphosphate 5′-triphosphate (pppGpp) synthesizing enzyme is present in the ribosomal fraction of . The enzyme is comparable to the (p)ppGpp synthetase I (stringent factor) in that it requires ribosomes, mRNA and codon-specific, uncharged tRNA. The ribosomal complex can be replaced by methanol. Ribosomes from do not function as effectors of the enzyme.