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Table 1 Kinetics for exogenous substrates on respiratory rate in nutrient-deficient cells

From: Activation of oxidative carbon metabolism by nutritional enrichment by photosynthesis and exogenous organic compounds in the red alga Cyanidioschyzon merolae: evidence for heterotrophic growth

Substrates V max K s (mM) S in (mM) R 2
l-Lactic acid 16.3 ± 1.2 6.7 ± 1.7 0.6 ± 0.3 0.94
Pyruvate (Na) 12.8 ± 0.9 3.7 ± 0.8 0.1 ± 0.1 0.96
Glycerol 7.1 ± 0.6 132 ± 34 10 ± 5 0.94
Glyoxylic acid 4.4 ± 0.2 47 ± 10 9 ± 3 0.95
Sucrose 4.3 ± 0.8 174 ± 82 21 ± 10 0.91
Mannitol 4.2 ± 1.1 296 ± 164 41 ± 16 0.93
Sorbitol 4.1 ± 0.4 231 ± 51 29 ± 5 0.97
Glucose 3.4 ± 0.2 105 ± 20 17 ± 4 0.96
Acetic acid 3.0 ± 0.6 0.43 ± 0.25 0.10 ± 0.06 0.84
Propionic acid 2.2 ± 0.2 0.24 ± 0.12 0.01 ± 0.05 0.84
Formic acid 1.8 ± 0.1 0.05 ± 0.03 0.03 ± 0.01 0.88
d-Lactic acid 1.8 ± 0.1 0.13 ± 0.07 0.1 ± 0.1 0.76
  1. Kinetic parameters were calculated by fitting to the modified Michaelis–Menten equation: \(v = V_{\text{max} } \left( {\left[ S \right] + \left[ {S_{\text{in}} } \right]} \right)/K_{\text{s}} + \left( {\left[ S \right] + \left[ {S_{\text{in}} } \right]} \right)\). V max (nmol O2 [mg protein]−1 min−1) indicates maximal velocity of respiration. K s indicates the substrate concentration which corresponds to the half of V max. S means the concentration of exogenous substrate. S in means hypothetical concentration of intracellular substrate. R 2 indicates coefficient of determination. Substrates are shown in descending order for the value of V max. Each value is an average ± standard deviation of triplicates