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Table 1 Distribution of non-homologous isofunctional enzymes among enzyme classes

From: Non-homologous isofunctional enzymes: A systematic analysis of alternative solutions in enzyme evolution

Enzyme class

Enzyme nodes in ENZYMEa

Enzyme nodes in KEGGa

Sequences with EC numbers

EC nodes with analogous enzymes

Fraction of the EC nodes

    

Two classes of enzymes

Three or more classes

 

Oxidoreductases (EC 1)

1343 (625)

575

98,166

31

5

5.8%

Transferases (EC 2)

1296 (683)

625

150,596

24

2

3.8%

Hydrolases (EC 3)c

930c (441)

427c

81,538

76

11

19.7%d

Lyases (EC 4)

469 (235)

210

45,074

15

3

7.7%

Isomerases (EC 5)

177 (106)

100

30,429

15

2

16.0%e

Ligases (EC 6)

148(97)

104

44,829

1

0

1.0%

Total

4,363

(2,187)

2,041

450,632

185

4.4%

  1. a - Only the EC nodes containing all 4 digits were considered; the numbers of EC nodes with at least one assigned protein sequence are shown in parentheses
  2. b - From the in KEGG database, based on a set of 718 complete genomes
  3. c - Peptidases (EC 3.4.x.x) were excluded from the analyzed set
  4. d - EC nodes with analogous enzymes are overrepresented (p < 1 × 10-12)
  5. e - Overrepresentation of EC nodes with analogous enzymes is not statistically significant (p ~ 0.08).
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Biology Direct

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