Table 9.

Classification of outer membrane porins (most from gram-negative bacteria) according to substrate specificity

SubstrateTC no.Family(-ies)
I.A. Nonselective
 Nonselective1.B.1, -2, -4, -6, -7, -8, -21, -23–26GBP, CP, BRP, OOP, RPP, MPP, OmpG, CBP, MBP, Opr, CDP
 Nonselective (slight cation selectivity)1.B.15.1.1RafY
I.C. Cations
 Fe3+ or Fe3+ chelate selective1.B.14.3.2OMR
 Metal ions1.B.17.2.1OMF
 Metal ions1.B.17.2.2OMF
I.D. Anions
 Anion selective1.B.1.6.1GBP
 Anion selective1.B.8MPP
 Anion selective1.B.13AEP
 Phosphate selective1.B.1.1.2GBP
 Phosphate selective1.B.5.1.1POP
 Pyrophosphate selective1.B.5.1.2POP
II.A. Sugars and polyols
 Glucose1.B.19.1.1OprB
 Maltooligosaccharide selective1.B.3.1.1SP
 Oligosaccharide selective1.B.3.1.2SP
II.B. Monocarboxylates
 Fatty acid selective1.B.9.1.1FadL
II.E. Others
 Toluene selective1.B.9.2.1FadL
III.A. Amides
 Amides, short chain1.B.16.1.1SAP
 Urea1.B.16.1.1SAP
IV.B. Nucleosides
 Nucleoside selective1.B.10.1.1Tsx
IV.C. Nucleotides
 Nucleotide selective1.B.1.1.4GBP
V.A. Vitamins
 Cobalamin selective1.B.14.3.1OMR
V.B. Enzyme and redox cofactors
 Heme1.B.14.2.3OMR
 Porphyrin1.B.14.3.1OMR
V.C. Iron-siderophores
 Iron complex selective1.B.14.1.1–4; 1.B.14.2–3OMR
 Fe3+-catecholate1.B.14.3.2OMR
 Fe3+-citrate1.B.14.1.2OMR
 Fe3+-coprogen1.B.14.1.3OMR
 Fe3+-enterobactin1.B.14.1.1OMR
 Ferrichrome1.B.14.1.4OMR
 Heme1.B.14.2.3OMR
 Heme1.B.20.3.1TEC
VI.A. Multiple drugs
 Drug (multiple) selective1.B.17.1.1OMF
 Drug (multiple) selective1.B.17.3.2OMF
 Drug (multiple) selective1.B.17.3.3OMF
VII.A. Carbohydrates
 Alginate (acidic polysaccharide)1.B.13.1.1AEP
 Capsular or exopolysaccharide selective1.B.18.1.1–2; 1.B.18.2.1OMA
 Lipooligosaccharide selective1.B.17.3.1OMF
 Polymannonate1.B.13.1.1AEP
 Polysaccharide selective1.B.13.1.1AEP
VII.B. Proteins
 Albomycin1.B.14.1.4OMR
 Colicin I selective1.B.14.3.2OMR
 Colicin M selective1.B.14.1.4OMR
 Colicin B selective1.B.14.1.1OMR
 Colicin D selective1.B.14.1.1OMR
 Fimbrial subunit selective1.B.11.1–3FUP
 Hemin selective1.B.14.2.3OMR
 Hemoglobin selective1.B.14.2.2OMR
 Protein (virulence factor) selective1.B.12AT
 Protein (hemolysin) selective1.B.17.1.1OMF
 Protein (hemolysin) selective1.B.20.1.2TEC
 Protein (hemagglutinin) selective1.B.20.2.1TEC
 Protein (proteases) selective1.B.17.1.2OMF
 Protein (cyclolysin) selective1.B.17.2.3OMF
 Protein (toxin) selective1.B.20.1.1TEC
 Transferrin selective1.B.14.2.1OMR
 Protein (competence factor) selective1.B.22.1.6Secretin
 Protein (secretory protein) selective1.B.22.1.1Secretin
 Protein (fimbrial subunit) selective1.B.22.1.3Secretin
 Protein (virulence factor) selective1.B.22.1.2; 1.B.22.1.4; 1.B.22.1.5Secretin
 Protein (phage) selective1.B.22.1.7Secretin