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Table 3 Kinetic parameters for pyruvate and NADH a

From: Diverse allosteric and catalytic functions of tetrameric d-lactate dehydrogenases from three Gram-negative bacteria

  kcat(s-1) S0.5(mM) kcat/S0.5(s-1 mM-1) Ki(mM)b n H c
Pyruvate      
pH 7.0      
FNLDH 80 (0.4) 0.34 (0.007) 230 (4)   
PALDH 400 (10) 0.10 (0.009) 4,000 (300) 1.8 (0.1)  
ECLDH 410 (8) 2.6 (0.09) 160 (2)   1.4 (0.05)
pH 8.0      
FNLDH 87 (1) 2.5 (0.06) 35 (0.6)   2.0 (0.1)
PALDH 240 (6) 1.2 (0.1) 200 (10)   0.77 (0.03)
ECLDH 380 (5) 7.6 (0.1) 50 (0.4)   2.2 (0.06)
pH 8.0 + FBPd      
FNLDH 100 (1) 1.7 (0.06) 60 (1)   1.3 (0.04)
PALDH 240 (4) 0.85 (0.04) 280 (6)   0.9 (0.02)
ECLDH 400 (5) 6.5 (0.1) 61 (1)   2.1 (0.09)
pH 8.0 + Mg+2e      
FNLDH 80 (1) 1.2 (0.04) 65 (1)   1.4 (0.05)
PALDH 290 (3) 0.36 (0.01) 820 (20) 20 (0.8)  
ECLDH 370 (6) 7.2 (0.2) 51 (1)   1.5 (0.07)
NADH      
pH 7.0      
FNLDH 98 (0.7) 0.022 (0.0005) 4,400 (80)   
PALDH 310 (2) 0.019 (0.0005) 17,000 (400)   
ECLDH 640 (20) 0.055 (0.004) 12,000 (500)   
pH 8.0      
FNLDH 90 (1) 0.036 (0.001) 2,500 (30)   1.6 (0.07)
PALDH 270 (2) 0.035 (0.0007) 7,700 (100)   
ECLDH 710 (8) 0.088 (0.002) 8,100 (100)   
pH 8.0 + FBPd      
FNLDH 80 (1) 0.028 (0.001) 2,800 (70)   1.5 (0.07)
PALDH 270 (2) 0.035 (0.001) 7,800 (100)   
ECLDH 730 (10) 0.092 (0.003) 8,000 (100)   
pH 8.0 + Mg+2e      
FNLDH 110 (2) 0.031 (0.001) 3,700 (70)   1.3 (0.05)
PALDH 270 (2) 0.035 (0.0009) 7,700 (100)   
ECLDH 690 (9) 0.090 (0.002) 7,700 (100)   
  1. aParameters were determined as described in the `Materials and methods' section, and standard deviations are shown in parentheses. bThe inhibition constants (Ki) are shown only for the cases that exhibited significant substrate inhibition. cHill coefficients (nH) are shown only for the cases that exhibited significant cooperativity. dThe concentrations of FBP for ECLDH, FNLDH, and PALDH were 5 mM, 10 mM, and 10 mM, respectively. eThe concentrations of Mg2+ for ECLDH, FNLDH, and PALDH were 2.4 mM, 5 mM, and 5 mM, respectively.