500
                                ATCase is one of the enzymes in the pyrimidine biosynthetic pathway. CTP, which is a  final product of the pathway, can bind to an allosteric site on the enzyme, rendering the active site nonfunctional. In this example, CTP is a__________inhibitor, and since CTP is a product of the pathway, this is an example of___________ inhibition.
                                1) non-competitive (allosteric),  2) feedback