The synthesis of 5-phosphoribosylamine from phosphoribosyl pyrophosphate (PRPP) is inhibited allosterically by ATP and GTP and activated by PRPP via feed forward activation. The enzyme that regulate this process is the enzyme amidophosphoribosyltransferase (AMPRT), which is stimulated by increased PRPP concentrations and is inhibited allosterically by ATP and GTP as well as IMP, AMP, and GMP.
The Sun looks bigger than other stars because its more closer to the earth than the stars.the farther anything is distant from us the tinier it will look
