stringent factor ( atp : gtp-3 ' pyrophosphotransferase ) has been purified from wild type bacillus subtilis and it has been shown that guanosine tetra- and pentaphosphate ( ppgpp and pppgpp ) are synthesized in vitro in the presence of ribosomes , unacylated trna and its specific codon , as has been demonstrated in escherichia coli .
C0004218
stringent factor
C0206339
pyrophosphotransferase