Carbamate kinase that plays a biosynthetic role in that it produces carbamoyl-phosphate. ATP + hydrogencarbonate + NH4(+) = ADP + carbamoyl phosphate + H(+) + H2O 50% activity is retained after 1 hour at 100 degrees Celsius or 3 hours at 95 degrees Celsius. Homodimer. Belongs to the carbamate kinase family.