2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	binding isotope effects indicate ground-state stabilization in the Michaelis complex, such as bonding environment, ribosyl pucker, and natural bond orbital charges	721669	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	mutational analysis supports for the push-pull model of catalysis, proposed catalytic mechanism of PcUP1, modeling, overview. Deprotonation of phosphate by Arg104, increases the negative charge on the phosphate oxygen, leading to repulsion between the electrons of phosphate oxygen and electron pairs of the endocylic ribosyl oxygen and the formation of an intermediate oxocarbenium ion. At the same time, the Gln206, Arg208 and Arg264-N1 hydrogen network-bond pulls electrons from the glycosidic bond onto the pyrimidine ring. These two actions work in concert to weaken the glycosidic bond. Arg39 pivots, to physically push the phosphate closer to the ribose moiety. After glycosidic bond cleavage, ribose-1-phosphate dissociates from the active pocket, and then an active water reprotonates the negatively charged purine. The final step is to release the neutral purine base	-, 760136	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	ordered bi-bi mechanism	638515, 638526, 638527	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	ordered bi-bi mechanism, phosphate binds before uridine and alpha-D-ribose 1-phosphate is released after uracil	638457	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	phosphate binds before uridine and ribose 1-phosphate is released after uracil	638526, 638527	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	random mechanism	638520	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	rapid-equilibrium random mechanism	-, 638518	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	sequential mechanism	638531, 638533, 638535	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	sequential rather than ping-pong mechanism, addition of substrate is random	638454	
2.4.2.3	uridine + phosphate = uracil + alpha-D-ribose 1-phosphate	steady-state random kinetic mechanism. Reaction follows an ANDN/SN2 mechanism where chemistry contributes significantly to the overall rate-limiting step of the reaction. No kinetically significant proton transfer step is involved at the transition state. Proton transfer to neutralize the leaving group is not part of transition state formation, consistent with an enzyme-stabilized anionic uracil as the leaving group. Kinetic analysis as a function of pH indicates one protonated group essential for catalysis and for substrate binding	721654