Skip to main content

Table 1 Kinetic parameters for various 2-ketoacids at pH 7.0 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
Glyoxylate      
FNLDH 11 (0.1) 18 (0.4) 0.70 (0.007)   
PALDH 880 (60) 6.8 (0.6) 130 (5) 44 (8)  
ECLDH 100 (5) 20 (2) 5.3 (0.2)   1.5 (0.09)
Pyruvate      
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)
2-Ketobutyrate      
FNLDH 140 (0.7) 0.31 (0.006) 440 (7)   
PALDH 100 (0.6) 0.64 (0.01) 150 (3)   
ECLDH 31 (2) 30 (4) 1.0 (0.05)   1.4 (0.08)
2-Ketovalerate      
FNLDH 140 (0.5) 0.68 (0.01) 200 (3)   
PALDH 69 (0.5) 4.0 (0.07) 18 (3)   
ECLDH N.D.d N.D. <0.01   
2-Ketoisovalerate      
FNLDH 120 (0.7) 3.5 (0.07) 35 (0.5)   
PALDH N.D. N.D. <0.4   
ECLDH N.D. N.D. <0.01   
2-Ketocaproate      
FNLDH 230 (1) 2.6 (0.06) 87 (1)   
PALDH 160 (1) 5.8 (0.1) 27 (0.4)   
ECLDH N.D. N.D. <0.01   
2-Ketoisocaproate      
FNLDH 200 (2) 3.8 (0.1) 53 (1)   
PALDH 39 (0.3) 12 (0.2) 3.2 (0.03)   
ECLDH N.D. N.D. <0.01   
Oxaloacetate      
FNLDH 80 (1) 2.5 (0.09) 31 (0.7) 140 (20)  
PALDH 410 (4) 1.7 (0.06) 230 (6)   
ECLDH 1,100 (200) 54 (10) 21 (0.6) 5.0 (1)  
Hydroxypyruvate      
FNLDH 160 (2) 18 (0.4) 8.7 (0.07)   
PALDH 420 (10) 3.0 (0.2) 140 (3) 19 (1)  
ECLDH 50 (0.5) 12 (0.3) 4.2 (0.06)   
Phenylpyruvate      
FNLDH 120 (7) 11 (0.9) 11 (0.3) 23 (3)  
PALDH 18 (0.2) 7.1 (0.2) 2.6 (0.04)   
ECLDH N.D. N.D. <0.01   
Hydroxyphenylpyruvate      
FNLDH N.D. N.D. <0.02   
PALDH N.D. N.D. <0.4   
ECLDH N.D. N.D. <0.01   
  1. aParameters were determined as described in the `Materials and methods' section, and standard deviations are shown in parentheses. bThe inhibition constants (Ki) and cHill coefficients (nH) are shown only for the cases in which significant substrate inhibition and cooperativity were observed, respectively. dN.D., not determined. The activities were too weak for determination of exact values.