Table 2.

PsAH and PsUC Kinetic Parameters in the Presence and Absence of 10‐fold Molar Excess of UAAP1 and UAAP2

	Allophanate hydrolase activity a
	k cat (s−1)	$K_{\mathrm{M}}^{\text{allophanate}}$ (mM)	k cat/K M (M−1s−1)
PsAH	3.64 ± 0.09c	0.24 ± 0.02	(1.5 ± 0.1) ×104
PsAH + UAAP1/2	3.67 ± 0.08	0.23 ± 0.02	(1.4 ± 0.1) ×104

	ATP hydrolysis activity b
	k cat (s−1)	K M a TP (μM); 50 mM urea	k cat/K M (M−1s−1)
PsUC	2.21 ± 0.06	8.0 ± 0.8	(2.8 ± 0.3) ×102
PsUC + UAAP1/2	2.08 ± 0.06	6.5 ± 0.7	(3.2 ± 0.4) ×102
	k cat (s−1)	K M, app urea (mM); 100 µM ATP	k cat/K M (M−1s−1)
PsUC	2.18 ± 0.08	3.8 ± 0.6	(5.7 ± 0.9) ×102
PsUC + UAAP1/2	2.16 ± 0.06	3.2 ± 0.4	(6.8 ± 0.8) ×102

^a50 mM HEPES (pH 7.3), 50 mM NaCl, 0.1–10 mM allophanate.

Reported errors represent the standard error from the nonlinear regression fit to the Michaelis–Menten equation. The curves were fit to the average of three independent velocity measurements at five different substrate concentrations.

Reported errors are propagated from the K _M and k _cat measurements in the preceding column.

^b50 mM HEPES (pH 7.3), 50 mM NaCl, 8 mM MgSO₄, 8 mM NaHCO₃, 0.5–50 mM Urea, 1–100 µM ATP.

Error analysis is as described for Table I.