Table II. Steady-state kinetic parameters of native and mutant HCT

Assays were performed as described in “Materials and Methods,” and average values ± se (n = 3) are also shown.

HCTShikimateQuinate5-CQA
KmVmaxVmax/KmKmVmaxVmax/KmKmVmaxVmax/Km
μmnkat mg−1μmnkat mg−1μmnkat mg−1
Native75.0 ± 8.513.55 ± 0.38180,700430 ± 1120.74 ± 0.101,720757 ± 1000.072 ± 0.00395.1
Lys-HCT30.7 ± 6.47.92 ± 0.34258,000608 ± 930.070 ± 0.004115
His-154-Asn35.4 ± 7.16.83 ± 0.44192,900351 ± 470.635 ± 0.0251,809
Leu-400-Thr640 ± 917.64 ± 0.4711,940162 ± 146.22 ± 0.2038,4001,930 ± 6100.063 ± 0.01032.6
Phe-402-Tyr316 ± 3111.32 ± 0.3835,820233 ± 203.73 ± 0.1416,010745 ± 900.223 ± 0.010299
Leu-400-Thr/Phe-402-Tyr1,160 ± 1913.64 ± 0.253,13799 ± 67.98 ± 0.1580,610210 ± 280.161 ± 0.005767