Review Article
How Supraphysiological Oxygen Levels in Standard Cell Culture Affect Oxygen-Consuming Reactions
Table 4
Km(O2) values for various O2-consuming enzymes.
| Enzyme | Product | Km(O2) (%) | Details | Reference |
| Nox2 | O2− | 3.5 | | [77] | Nox2 | O2− | 3.1 | | [78] | Nox2 | O2− | 2-3 | | [19] | Nox2 | O2− | 2-3 | | [79] | Nox4 | H2O2 | 18 | | [78] | Nox4 | H2O2 | 18 | | [19] | Nox4 | H2O2 | 16–20 | | [79] | nNOS | NO | 2.3 | Purified bovine enzyme | [45] | nNOS | NO/O2− | 2.2 | Partially uncoupled rat enzyme | [42, 43] | O2− | 3.4 | Fully uncoupled rat enzyme | nNOS | NO | 15.7 | Purified rat enzyme | [47] | nNOS | NO | 39.8 | Purified rat enzyme | [80] | nNOS | NO | 28.5 | Kinetic model based on rat enzyme data | [81, 82] | eNOS | NO | 0.8 | Purified bovine enzyme | [45] | eNOS | NO | 0.3 | Kinetic model based on rat enzyme data | [82, 83] | iNOS | NO | 0.63 ± 0.09 | Purified bovine enzyme | [45] | iNOS | NO | 11.0 | Isolated enzyme assay | [84] | iNOS | NO | 10.6 | Kinetic model | [82] | NOS | NO | 3.1–10.8 | Unspecified isoform | [48, 85] | XO | O2·−/H2O2 | 2.2–6.8 | Isolated from bovine milk | Fridovich et al. 1962, 1964 | MAO | H2O2 | 3.4–28 | Mammalian enzymes; various substrates | [86–88]; reviewed in [57] | HO | CO, iron, and bilirubin | <1.5 | Unspecified isoform from chicken liver | [59] | LOX | H2O2 | 1–2.6 | Unspecified isoform | [65] | COX-1 | Various | 0.4–3.1 | Arachidonic acid substrate | [63, 89–91] | COX-2 | Various | 1.3–1.5 | Arachidonic acid substrate | [63, 65] | PHD | Modified HIF | 41–46 | Various substrates | [92] | FIH | Modified HIF | 4–12 | Various substrates | [92] |
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Nox: NADPH oxidase; NOS: nitric oxide synthase; XO: xanthine oxidase; MAO: monoamine oxidase; HO: heme oxygenase; LOX: lipoxygenase; COX: cyclooxygenase; PHD: prolyl hydroxylase; FIH: factor inhibiting HIF-1.
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