text: user1525: Note: this question has also been asked on Biostars
  I need the get the list of gene names involved in glycolysis (to put an example). Not manually, I need to do this in a script. Ideally with Python. I think KEGG is the proper database to do this, but any other (free) suggestion would do.
  How can I do it?
  
  user73: Answers from Biostars:
  GeneSCF 'prepare_database' module will extract all the pathways with corresponding genes as simple table format in plain text file. Check 'Two step process' (sub-heading) from the provided link (First step will do your job).
  
  You can use KEGG REST API for extracting gene names from the pathway. Python request library can be used to make the REST calls to KEGG REST API and query information. Please follow this tutorial if you are a newbie to the Python programming and REST web services.
  
  user298: I whipped this little script up using the KEGG API:
  #!/usr/bin/env python3
  import urllib.request
  import re
  import sys
  pathway = 'hsa00010' # glycolysis
  url = "http://rest.kegg.jp/get/" + pathway
  with urllib.request.urlopen(url) as f:
      lines = f.read().decode('utf-8').splitlines()
      want = 0
      for line in lines:
          fields = line.split()
          ## The list of genes starts here
          if fields[0] == 'GENE':
              want = 1
              ## The line with GENE is different
              print(fields[2].rstrip(';'))
          ## We reached the next section of the file
          elif want == 1 and re.match('^\S', line):
              sys.exit();
          ## We're still in the list of genes
          if want == 1 and len(fields)>1:
              print(fields[1].rstrip(';'))
  
  
  user71: using the REST API of togows: one can fetch a json structure of the genes associated to a kegg pathway. eg: http://togows.org/entry/kegg-pathway/hsa00010/genes.json
  [
    {
      "3101": "HK3; hexokinase 3 [KO:K00844] [EC:2.7.1.1]",
      "3098": "HK1; hexokinase 1 [KO:K00844] [EC:2.7.1.1]",
      "3099": "HK2; hexokinase 2 [KO:K00844] [EC:2.7.1.1]",
      "80201": "HKDC1; hexokinase domain containing 1 [KO:K00844] [EC:2.7.1.1]",
      "2645": "GCK; glucokinase [KO:K12407] [EC:2.7.1.2]",
      "2821": "GPI; glucose-6-phosphate isomerase [KO:K01810] [EC:5.3.1.9]",
      "5213": "PFKM; phosphofructokinase, muscle [KO:K00850] [EC:2.7.1.11]",
      "5214": "PFKP; phosphofructokinase, platelet [KO:K00850] [EC:2.7.1.11]",
      "5211": "PFKL; phosphofructokinase, liver type [KO:K00850] [EC:2.7.1.11]",
      "2203": "FBP1; fructose-bisphosphatase 1 [KO:K03841] [EC:3.1.3.11]",
      "8789": "FBP2; fructose-bisphosphatase 2 [KO:K03841] [EC:3.1.3.11]",
      "230": "ALDOC; aldolase, fructose-bisphosphate C [KO:K01623] [EC:4.1.2.13]",
      "226": "ALDOA; aldolase, fructose-bisphosphate A [KO:K01623] [EC:4.1.2.13]",
      "229": "ALDOB; aldolase, fructose-bisphosphate B [KO:K01623] [EC:4.1.2.13]",
      "7167": "TPI1; triosephosphate isomerase 1 [KO:K01803] [EC:5.3.1.1]",
      "2597": "GAPDH; glyceraldehyde-3-phosphate dehydrogenase [KO:K00134] [EC:1.2.1.12]",
      "26330": "GAPDHS; glyceraldehyde-3-phosphate dehydrogenase, spermatogenic [KO:K10705] [EC:1.2.1.12]",
      "5232": "PGK2; phosphoglycerate kinase 2 [KO:K00927] [EC:2.7.2.3]",
      "5230": "PGK1; phosphoglycerate kinase 1 [KO:K00927] [EC:2.7.2.3]",
      "5223": "PGAM1; phosphoglycerate mutase 1 [KO:K01834] [EC:5.4.2.11]",
      "5224": "PGAM2; phosphoglycerate mutase 2 [KO:K01834] [EC:5.4.2.11]",
      "441531": "PGAM4; phosphoglycerate mutase family member 4 [KO:K01834] [EC:5.4.2.11]",
      "2027": "ENO3; enolase 3 [KO:K01689] [EC:4.2.1.11]",
      "2026": "ENO2; enolase 2 [KO:K01689] [EC:4.2.1.11]",
      "2023": "ENO1; enolase 1 [KO:K01689] [EC:4.2.1.11]",
      "5315": "PKM; pyruvate kinase, muscle [KO:K00873] [EC:2.7.1.40]",
      "5313": "PKLR; pyruvate kinase, liver and RBC [KO:K12406] [EC:2.7.1.40]",
      "5161": "PDHA2; pyruvate dehydrogenase alpha 2 [KO:K00161] [EC:1.2.4.1]",
      "5160": "PDHA1; pyruvate dehydrogenase alpha 1 [KO:K00161] [EC:1.2.4.1]",
      "5162": "PDHB; pyruvate dehydrogenase (lipoamide) beta [KO:K00162] [EC:1.2.4.1]",
      "1737": "DLAT; dihydrolipoamide S-acetyltransferase [KO:K00627] [EC:2.3.1.12]",
      "1738": "DLD; dihydrolipoamide dehydrogenase [KO:K00382] [EC:1.8.1.4]",
      "160287": "LDHAL6A; lactate dehydrogenase A like 6A [KO:K00016] [EC:1.1.1.27]",
      "92483": "LDHAL6B; lactate dehydrogenase A like 6B [KO:K00016] [EC:1.1.1.27]",
      "3939": "LDHA; lactate dehydrogenase A [KO:K00016] [EC:1.1.1.27]",
      "3945": "LDHB; lactate dehydrogenase B [KO:K00016] [EC:1.1.1.27]",
      "3948": "LDHC; lactate dehydrogenase C [KO:K00016] [EC:1.1.1.27]",
      "124": "ADH1A; alcohol dehydrogenase 1A (class I), alpha polypeptide [KO:K13951] [EC:1.1.1.1]",
      "125": "ADH1B; alcohol dehydrogenase 1B (class I), beta polypeptide [KO:K13951] [EC:1.1.1.1]",
      "126": "ADH1C; alcohol dehydrogenase 1C (class I), gamma polypeptide [KO:K13951] [EC:1.1.1.1]",
      "131": "ADH7; alcohol dehydrogenase 7 (class IV), mu or sigma polypeptide [KO:K13951] [EC:1.1.1.1]",
      "127": "ADH4; alcohol dehydrogenase 4 (class II), pi polypeptide [KO:K13980] [EC:1.1.1.1]",
      "128": "ADH5; alcohol dehydrogenase 5 (class III), chi polypeptide [KO:K00121] [EC:1.1.1.1 1.1.1.284]",
      "130": "ADH6; alcohol dehydrogenase 6 (class V) [KO:K13952] [EC:1.1.1.1]",
      "10327": "AKR1A1; aldo-keto reductase family 1 member A1 [KO:K00002] [EC:1.1.1.2]",
      "217": "ALDH2; aldehyde dehydrogenase 2 family (mitochondrial) [KO:K00128] [EC:1.2.1.3]",
      "224": "ALDH3A2; aldehyde dehydrogenase 3 family member A2 [KO:K00128] [EC:1.2.1.3]",
      "219": "ALDH1B1; aldehyde dehydrogenase 1 family member B1 [KO:K00128] [EC:1.2.1.3]",
      "501": "ALDH7A1; aldehyde dehydrogenase 7 family member A1 [KO:K14085] [EC:1.2.1.3 1.2.1.8 1.2.1.31]",
      "223": "ALDH9A1; aldehyde dehydrogenase 9 family member A1 [KO:K00149] [EC:1.2.1.3 1.2.1.47]",
      "221": "ALDH3B1; aldehyde dehydrogenase 3 family member B1 [KO:K00129] [EC:1.2.1.5]",
      "222": "ALDH3B2; aldehyde dehydrogenase 3 family member B2 [KO:K00129] [EC:1.2.1.5]",
      "220": "ALDH1A3; aldehyde dehydrogenase 1 family member A3 [KO:K00129] [EC:1.2.1.5]",
      "218": "ALDH3A1; aldehyde dehydrogenase 3 family member A1 [KO:K00129] [EC:1.2.1.5]",
      "84532": "ACSS1; acyl-CoA synthetase short chain family member 1 [KO:K01895] [EC:6.2.1.1]",
      "55902": "ACSS2; acyl-CoA synthetase short chain family member 2 [KO:K01895] [EC:6.2.1.1]",
      "130589": "GALM; galactose mutarotase [KO:K01785] [EC:5.1.3.3]",
      "5236": "PGM1; phosphoglucomutase 1 [KO:K01835] [EC:5.4.2.2]",
      "55276": "PGM2; phosphoglucomutase 2 [KO:K15779] [EC:5.4.2.7 5.4.2.2]",
      "2538": "G6PC; glucose-6-phosphatase catalytic subunit [KO:K01084] [EC:3.1.3.9]",
      "57818": "G6PC2; glucose-6-phosphatase catalytic subunit 2 [KO:K01084] [EC:3.1.3.9]",
      "92579": "G6PC3; glucose-6-phosphatase catalytic subunit 3 [KO:K01084] [EC:3.1.3.9]",
      "83440": "ADPGK; ADP dependent glucokinase [KO:K08074] [EC:2.7.1.147]",
      "669": "BPGM; bisphosphoglycerate mutase [KO:K01837] [EC:5.4.2.11 5.4.2.4]",
      "9562": "MINPP1; multiple inositol-polyphosphate phosphatase 1 [KO:K03103] [EC:3.1.3.80 3.1.3.62]",
      "5105": "PCK1; phosphoenolpyruvate carboxykinase 1 [KO:K01596] [EC:4.1.1.32]",
      "5106": "PCK2; phosphoenolpyruvate carboxykinase 2, mitochondrial [KO:K01596] [EC:4.1.1.32]"
    }
  ]
  
  
original_text: 1525: <p><em>Note: this question has also been asked on <a href="https://www.biostars.org/p/274321/" rel="nofollow noreferrer">Biostars</a></em></p>
  
  <p>I need the get the list of gene names involved in glycolysis (to put an example). Not manually, I need to do this in a script. Ideally with Python. I think KEGG is the proper database to do this, but any other (free) suggestion would do.</p>
  
  <p>How can I do it?</p>
   73: <p>Answers from Biostars:</p>
  
  <p><a href="https://www.biostars.org/p/108669/" rel="nofollow noreferrer">GeneSCF</a> 'prepare_database' module will extract all the pathways with corresponding genes as simple table format in plain text file. Check 'Two step process' (sub-heading) from the provided link (First step will do your job).</p>
  
  <hr>
  
  <p>You can use <a href="http://www.kegg.jp/kegg/docs/keggapi.html" rel="nofollow noreferrer">KEGG REST API</a> for extracting gene names from the pathway. <a href="http://docs.python-requests.org/en/master/" rel="nofollow noreferrer">Python request library</a> can be used to make the REST calls to KEGG REST API and query information. Please follow <a href="http://www.pythonforbeginners.com/requests/using-requests-in-python" rel="nofollow noreferrer">this tutorial</a> if you are a newbie to the Python programming and REST web services.</p>
   298: <p>I whipped this little script up using the <a href="http://www.kegg.jp/kegg/rest/" rel="noreferrer">KEGG API</a>:</p>
  
  <pre class="lang-python prettyprint-override"><code>#!/usr/bin/env python3
  import urllib.request
  import re
  import sys
  pathway = 'hsa00010' # glycolysis
  url = "http://rest.kegg.jp/get/" + pathway
  with urllib.request.urlopen(url) as f:
      lines = f.read().decode('utf-8').splitlines()
      want = 0
      for line in lines:
          fields = line.split()
          ## The list of genes starts here
          if fields[0] == 'GENE':
              want = 1
              ## The line with GENE is different
              print(fields[2].rstrip(';'))
          ## We reached the next section of the file
          elif want == 1 and re.match('^\S', line):
              sys.exit();
          ## We're still in the list of genes
          if want == 1 and len(fields)&gt;1:
              print(fields[1].rstrip(';'))
  </code></pre>
   71: <p>using the REST API of <a href="http://togows.dbcls.jp/" rel="noreferrer">togows</a>: one can fetch a json structure of the genes associated to a kegg pathway. eg: <a href="http://togows.org/entry/kegg-pathway/hsa00010/genes.json" rel="noreferrer">http://togows.org/entry/kegg-pathway/hsa00010/genes.json</a></p>
  
  <pre><code>[
    {
      "3101": "HK3; hexokinase 3 [KO:K00844] [EC:2.7.1.1]",
      "3098": "HK1; hexokinase 1 [KO:K00844] [EC:2.7.1.1]",
      "3099": "HK2; hexokinase 2 [KO:K00844] [EC:2.7.1.1]",
      "80201": "HKDC1; hexokinase domain containing 1 [KO:K00844] [EC:2.7.1.1]",
      "2645": "GCK; glucokinase [KO:K12407] [EC:2.7.1.2]",
      "2821": "GPI; glucose-6-phosphate isomerase [KO:K01810] [EC:5.3.1.9]",
      "5213": "PFKM; phosphofructokinase, muscle [KO:K00850] [EC:2.7.1.11]",
      "5214": "PFKP; phosphofructokinase, platelet [KO:K00850] [EC:2.7.1.11]",
      "5211": "PFKL; phosphofructokinase, liver type [KO:K00850] [EC:2.7.1.11]",
      "2203": "FBP1; fructose-bisphosphatase 1 [KO:K03841] [EC:3.1.3.11]",
      "8789": "FBP2; fructose-bisphosphatase 2 [KO:K03841] [EC:3.1.3.11]",
      "230": "ALDOC; aldolase, fructose-bisphosphate C [KO:K01623] [EC:4.1.2.13]",
      "226": "ALDOA; aldolase, fructose-bisphosphate A [KO:K01623] [EC:4.1.2.13]",
      "229": "ALDOB; aldolase, fructose-bisphosphate B [KO:K01623] [EC:4.1.2.13]",
      "7167": "TPI1; triosephosphate isomerase 1 [KO:K01803] [EC:5.3.1.1]",
      "2597": "GAPDH; glyceraldehyde-3-phosphate dehydrogenase [KO:K00134] [EC:1.2.1.12]",
      "26330": "GAPDHS; glyceraldehyde-3-phosphate dehydrogenase, spermatogenic [KO:K10705] [EC:1.2.1.12]",
      "5232": "PGK2; phosphoglycerate kinase 2 [KO:K00927] [EC:2.7.2.3]",
      "5230": "PGK1; phosphoglycerate kinase 1 [KO:K00927] [EC:2.7.2.3]",
      "5223": "PGAM1; phosphoglycerate mutase 1 [KO:K01834] [EC:5.4.2.11]",
      "5224": "PGAM2; phosphoglycerate mutase 2 [KO:K01834] [EC:5.4.2.11]",
      "441531": "PGAM4; phosphoglycerate mutase family member 4 [KO:K01834] [EC:5.4.2.11]",
      "2027": "ENO3; enolase 3 [KO:K01689] [EC:4.2.1.11]",
      "2026": "ENO2; enolase 2 [KO:K01689] [EC:4.2.1.11]",
      "2023": "ENO1; enolase 1 [KO:K01689] [EC:4.2.1.11]",
      "5315": "PKM; pyruvate kinase, muscle [KO:K00873] [EC:2.7.1.40]",
      "5313": "PKLR; pyruvate kinase, liver and RBC [KO:K12406] [EC:2.7.1.40]",
      "5161": "PDHA2; pyruvate dehydrogenase alpha 2 [KO:K00161] [EC:1.2.4.1]",
      "5160": "PDHA1; pyruvate dehydrogenase alpha 1 [KO:K00161] [EC:1.2.4.1]",
      "5162": "PDHB; pyruvate dehydrogenase (lipoamide) beta [KO:K00162] [EC:1.2.4.1]",
      "1737": "DLAT; dihydrolipoamide S-acetyltransferase [KO:K00627] [EC:2.3.1.12]",
      "1738": "DLD; dihydrolipoamide dehydrogenase [KO:K00382] [EC:1.8.1.4]",
      "160287": "LDHAL6A; lactate dehydrogenase A like 6A [KO:K00016] [EC:1.1.1.27]",
      "92483": "LDHAL6B; lactate dehydrogenase A like 6B [KO:K00016] [EC:1.1.1.27]",
      "3939": "LDHA; lactate dehydrogenase A [KO:K00016] [EC:1.1.1.27]",
      "3945": "LDHB; lactate dehydrogenase B [KO:K00016] [EC:1.1.1.27]",
      "3948": "LDHC; lactate dehydrogenase C [KO:K00016] [EC:1.1.1.27]",
      "124": "ADH1A; alcohol dehydrogenase 1A (class I), alpha polypeptide [KO:K13951] [EC:1.1.1.1]",
      "125": "ADH1B; alcohol dehydrogenase 1B (class I), beta polypeptide [KO:K13951] [EC:1.1.1.1]",
      "126": "ADH1C; alcohol dehydrogenase 1C (class I), gamma polypeptide [KO:K13951] [EC:1.1.1.1]",
      "131": "ADH7; alcohol dehydrogenase 7 (class IV), mu or sigma polypeptide [KO:K13951] [EC:1.1.1.1]",
      "127": "ADH4; alcohol dehydrogenase 4 (class II), pi polypeptide [KO:K13980] [EC:1.1.1.1]",
      "128": "ADH5; alcohol dehydrogenase 5 (class III), chi polypeptide [KO:K00121] [EC:1.1.1.1 1.1.1.284]",
      "130": "ADH6; alcohol dehydrogenase 6 (class V) [KO:K13952] [EC:1.1.1.1]",
      "10327": "AKR1A1; aldo-keto reductase family 1 member A1 [KO:K00002] [EC:1.1.1.2]",
      "217": "ALDH2; aldehyde dehydrogenase 2 family (mitochondrial) [KO:K00128] [EC:1.2.1.3]",
      "224": "ALDH3A2; aldehyde dehydrogenase 3 family member A2 [KO:K00128] [EC:1.2.1.3]",
      "219": "ALDH1B1; aldehyde dehydrogenase 1 family member B1 [KO:K00128] [EC:1.2.1.3]",
      "501": "ALDH7A1; aldehyde dehydrogenase 7 family member A1 [KO:K14085] [EC:1.2.1.3 1.2.1.8 1.2.1.31]",
      "223": "ALDH9A1; aldehyde dehydrogenase 9 family member A1 [KO:K00149] [EC:1.2.1.3 1.2.1.47]",
      "221": "ALDH3B1; aldehyde dehydrogenase 3 family member B1 [KO:K00129] [EC:1.2.1.5]",
      "222": "ALDH3B2; aldehyde dehydrogenase 3 family member B2 [KO:K00129] [EC:1.2.1.5]",
      "220": "ALDH1A3; aldehyde dehydrogenase 1 family member A3 [KO:K00129] [EC:1.2.1.5]",
      "218": "ALDH3A1; aldehyde dehydrogenase 3 family member A1 [KO:K00129] [EC:1.2.1.5]",
      "84532": "ACSS1; acyl-CoA synthetase short chain family member 1 [KO:K01895] [EC:6.2.1.1]",
      "55902": "ACSS2; acyl-CoA synthetase short chain family member 2 [KO:K01895] [EC:6.2.1.1]",
      "130589": "GALM; galactose mutarotase [KO:K01785] [EC:5.1.3.3]",
      "5236": "PGM1; phosphoglucomutase 1 [KO:K01835] [EC:5.4.2.2]",
      "55276": "PGM2; phosphoglucomutase 2 [KO:K15779] [EC:5.4.2.7 5.4.2.2]",
      "2538": "G6PC; glucose-6-phosphatase catalytic subunit [KO:K01084] [EC:3.1.3.9]",
      "57818": "G6PC2; glucose-6-phosphatase catalytic subunit 2 [KO:K01084] [EC:3.1.3.9]",
      "92579": "G6PC3; glucose-6-phosphatase catalytic subunit 3 [KO:K01084] [EC:3.1.3.9]",
      "83440": "ADPGK; ADP dependent glucokinase [KO:K08074] [EC:2.7.1.147]",
      "669": "BPGM; bisphosphoglycerate mutase [KO:K01837] [EC:5.4.2.11 5.4.2.4]",
      "9562": "MINPP1; multiple inositol-polyphosphate phosphatase 1 [KO:K03103] [EC:3.1.3.80 3.1.3.62]",
      "5105": "PCK1; phosphoenolpyruvate carboxykinase 1 [KO:K01596] [EC:4.1.1.32]",
      "5106": "PCK2; phosphoenolpyruvate carboxykinase 2, mitochondrial [KO:K01596] [EC:4.1.1.32]"
    }
  ]
  </code></pre>
  