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Table 1 Kinetic parameters for M. tb ICD-1 and M. tb ICD-2 with respect to Mg++ and Zn++

From: Comparison of Mycobacterium tuberculosis isocitrate dehydrogenases (ICD-1 and ICD-2) reveals differences in coenzyme affinity, oligomeric state, pH tolerance and phylogenetic affiliation

Kinetic parameters With MgCl2 With ZnCl2
M. tb ICD-1   
Km(isocitrate) 10 μM ± 5 22 μM ± 7
Vmax(isocitrate) 380 μM NADPH/min 190 μM NADPH/min
Kcat (isocitrate) 3.8 μM NADPH/min/pM enzyme 1.9 μM NADPH/min/pM enzyme
Km(NADP+) 125 μM ± 5 -
Vmax(NADP+) 400 μM NADPH/min -
Kcat (NADP+) 4 μM NADPH/min/pM enzyme -
M. tb ICD-2   
Km(isocitrate) 20 μM ± 1 No activity
Vmax(isocitrate) 371.3 μM NADPH/min  
Kcat (isocitrate) 37.13 μM NADPH/min/pM enzyme  
Km(NADP+) 19.6 μM ± 6  
Vmax(NADP+) 374 μM NADPH/min  
Kcat (NADP+) 37.4 μM NADPH/min/pM enzyme  
Ki(NADPH) 0.46 × 10-5 M.