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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