Catalyzes the ATP-dependent amination of UTP to CTP with either L-glutamine or ammonia as the source of nitrogen. ATP + H2O + L-glutamine + UTP = ADP + CTP + 2 H(+) + L-glutamate + phosphate Activated by GTP and inhibited by CTP. Optimum pH is 8.0. Pyrimidine metabolism; CTP biosynthesis via de novo pathway; CTP from UDP: step 2/2. Homodimer. Oligomerizes to a tetramer in the presence of its substrates UTP and ATP. Present with 57600 molecules/cell in log phase SD medium. Belongs to the CTP synthase family.