| Internalin domain protein | FSU_0307 | C9RPU0 | 1 |
| Intracellular growth locus protein A | iglA FTN_1324 | A0Q7I5 | 1 |
| Intracellular growth locus protein B | OOM_0932 | I2AZ00 | 1 |
| Intracellular growth locus protein C | iglC FTN_1322 | A0Q7I3 | 1 |
| Intracellular growth locus protein D | OOM_0934 | I2AZ02 | 1 |
| Intracellular growth locus, subunit B | iglB2 iglB1 FTT_1358c FTT_1713c | Q5NEC4 | 1 |
| Intracellular growth locus, subunit C | Fphi_1366 | B0TYB5 | 1 |
| Intracellular growth locus, subunit C | OOM_0933 | I2AZ01 | 1 |
| Intracellular growth locus, subunit C | iglC2 iglC1 FTT_1357c FTT_1712c | Q5NEC5 | 1 |
| Intracellular growth locus, subunit D | iglD2 iglD1 FTT_1356c FTT_1711c | Q5NEC6 | 1 |
| Invasin IpaA (70 kDa antigen) | ipaA CP0125 | P18010 | 1 |
| Invasin IpaB (62 kDa antigen) | ipaB CP0128 | P18011 | 1 |
| Invasin IpaD (36 kDa membrane antigen) | ipaD CP0126 | P18013 | 1 |
| Invasion protein iagB | iagB STM2877 | P0CL15 | 1 |
| Involved in transformation required for DNA uptake but not for binding Related to ATP-dependent RNA/DNA helicases | comFA spr2013 | Q8CWM9 | 1 |
| Iron chelate uptake ABC transporter, FeCT family, solute-binding protein | AC1_1482 | B1R8Q9 | 1 |
| Iron complex transport system ATP-binding protein | LMRG_01107 | A0A0H3GHL0 | 1 |
| Iron compound ABC transporter, periplasmic iron compound-binding protein | MXAN_6000 | Q1CZN8 | 1 |
| Iron compound ABC transporter, substrate-binding protein, putative | SAOUHSC_00613 | Q2G0F6 | 1 |
| Iron hydrogenase | hydA AC1_2913 | B1R7N8 | 1 |
| Iron transport protein | sitA SSON_1750 | Q3Z1C5 | 1 |
| Iron uptake system component EfeO | efeO SSON_1037 | Q3Z397 | 1 |
| Iron(3+)-hydroxamate import system permease protein FhuB (Ferric hydroxamate uptake protein B) (Ferrichrome transport system permease protein FhuB) (Ferrichrome uptake protein FhuB) (Iron(III)-hydroxamate import system permease protein FhuB) | fhuB b0153 JW0149 | P06972 | 1 |
| Iron(III) ABC transporter, periplasmic binding protein | NMB1989 | Q9JXL2 | 1 |
| Iron(III) ABC transporter, periplasmic iron-compound-binding protein | VC_0608 | Q9KUB5 | 1 |
| Iron(III) ABC transporter, periplasmic iron-compound-binding protein | VC_A0227 | Q9KMU2 | 1 |
| Iron(III) ABC transporter, periplasmic iron-compound-binding protein | VS_2518 | B7VJL1 | 1 |
| Iron(III) compound receptor | VC_0200 | Q9KVE6 | 1 |
| IRON(III) DICITRATE TRANSPORT PROTEIN | fecA_1 jhp_0626 | Q9ZLF4 | 1 |
| Iron(III)-binding periplasmic protein | sfuA YPO2958 | Q7CJD9 | 1 |
| Iron-binding protein | AC1_1620 | B1R5Q7 | 1 |
| Iron-binding protein IscA (Iron-sulfur cluster assembly protein) | iscA SSON_2610 | Q3YZ24 | 1 |
| Iron-containing alcohol dehydrogenase | B195_07100 | M5QK97 | 1 |
| Iron-dependent extradiol dioxygenase (EC 1.13.11.25) | hsaC bphC Rv3568c | P9WNW7 | 1 |
| Iron-regulated membrane protein | yfiB KPN_02926 | A6TCL1 | 1 |
| Iron-regulated outer membrane virulence protein | irgA VC_0475 | P0C6R0 | 1 |
| Iron-regulated surface determinant protein A (Fur-regulated protein A) (Staphylococcal transferrin-binding protein A) | isdA frpA stbA SAOUHSC_01081 | Q2FZE9 | 1 |
| Iron-sulfur cluster assembly scaffold protein IscU | HPSD74_0330 | U4SLA0 | 1 |
| Iron-sulfur cluster assembly scaffold protein IscU (Sulfur acceptor protein IscU) | iscU nifU M5005_Spy0245 SPy_0289 | Q9A1G2 | 1 |
| Iron-sulfur cluster carrier protein | B195_11126 | M5QIX6 | 1 |
| Iron-sulfur cluster carrier protein | PA3481 | Q9HYC8 | 1 |
| Iron-sulfur cluster carrier protein | SAOUHSC_02417 | Q2FW86 | 1 |
| Iron-sulfur cluster-binding protein | PP_4259 | Q88F40 | 1 |
| Iron-sulfur cluster-binding protein | VSAK1_11485 | A6D829 | 1 |
| Iron-sulphur subunit of succinate dehydrogenase, putative | SAOUHSC_01105 | Q2FZC7 | 1 |
| IS66 family element, Orf2 | SPJ_2239 | C1CHL2 | 1 |
| Isocaprenoyl-CoA:2-hydroxyisocaproate CoA-transferase (EC 2.8.3.-) | hadA CD630_03950 | Q188I3 | 1 |
| Isocitrate dehydrogenase | icd FTN_1434 | A0Q7T7 | 1 |
| Isocitrate dehydrogenase (EC 1.1.1.42) | B195_20510 | M5QC86 | 1 |
| Isocitrate dehydrogenase (EC 1.1.1.42) | idh FTT_1526c | Q5NET6 | 1 |
| Isocitrate dehydrogenase (NADP(+)) (EC 1.1.1.42) | Fphi_1241 | B0TXK8 | 1 |
| Isocitrate dehydrogenase kinase/phosphatase (IDH kinase/phosphatase) (IDHK/P) (EC 2.7.11.5) (EC 3.1.3.-) | aceK PA1376 | Q9I3W8 | 1 |
| Isocitrate dehydrogenase [NADP] (EC 1.1.1.42) | icd YPO1641 | Q0WGD6 | 1 |
| Isocitrate dehydrogenase [NADP] (EC 1.1.1.42) | icd HPSD74_2195 | U4S7Z9 | 1 |
| Isocitrate dehydrogenase [NADP] (EC 1.1.1.42) | icdA SCH_1189 | Q57QB6 | 1 |
| Isocitrate dehydrogenase [NADP] (EC 1.1.1.42) | SAOUHSC_01801 | Q2FXN4 | 1 |
| Isocitrate dehydrogenase [NADP] (EC 1.1.1.42) | KW89_2009 | A0A0K2DYP3 | 1 |
| Isocitrate dehydrogenase [NADP] (IDH) (EC 1.1.1.42) (IDP) (NADP(+)-specific ICDH) (Oxalosuccinate decarboxylase) | icd HP_0027 | P56063 | 1 |
| Isocitrate dehydrogenase [NADP] (IDH) (EC 1.1.1.42) (IDP) (NADP(+)-specific ICDH) (Oxalosuccinate decarboxylase) | icd Rv3339c MTV016.39c | P9WKL1 | 1 |
| Isocitrate dehydrogenase, NADP-dependent, monomeric type (EC 1.1.1.42) | icd NMB0920 | Q9JZS1 | 1 |
| Isocitrate lyase | ECs4933 | A0A0H3JR68 | 1 |
| Isocitrate lyase (EC 4.1.3.1) | aceA YPO3725 | Q7CLE1 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS Fphi_0396 | B0TZQ5 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS FTN_0441 | A0Q529 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS CPC_2931 | B1BHQ0 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS spr1502 | Q8DNW4 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS PP_0603 | Q88Q92 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS YPO0475 y3700 YP_3705 | Q8ZIM0 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS SF0022 S0025 | Q83MH2 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS SSON_0031 | Q3Z5Y4 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS HPSD74_1088 | U4SHX9 | 1 |
| Isoleucine--tRNA ligase (EC 6.1.1.5) (Isoleucyl-tRNA synthetase) (IleRS) | ileS SPy_1513 M5005_Spy1243 | Q99YW3 | 1 |
| Isopentenyl-diphosphate delta-isomerase (IPP isomerase) (EC 5.3.3.2) (Isopentenyl diphosphate:dimethylallyl diphosphate isomerase) (Isopentenyl pyrophosphate isomerase) (Type 2 isopentenyl diphosphate isomerase) (IDI-2) | fni SPy_0879 M5005_Spy0685 | P65103 | 1 |
| Isoprenyl transferase (EC 2.5.1.-) | uppS SPy_1965 M5005_Spy1676 | Q99XY1 | 1 |
| Isoprenyl transferase (EC 2.5.1.-) | uppS CD630_21360 | Q185S4 | 1 |
| Isoprenyl transferase (EC 2.5.1.-) | LMRG_00765 | A0A0H3GGI5 | 1 |
| Isovaleryl-CoA dehydrogenase | B195_07695 | M5QYF5 | 1 |
| KAP P-loop | VSAK1_26040 | A6D0Z8 | 1 |
| KAP P-loop domain protein | VSAK1_00532 | A6D167 | 1 |
| KefC potassium CPA2 transporter | HPSD74_1097 | U4SI66 | 1 |
| Kelch domain protein | MXAN_5265 | Q1D1Q6 | 1 |
| Keto-hydroxyglutarate-aldolase/keto-deoxy-phosphogluconate aldolase (EC 4.1.3.16) | VSAK1_20649 | A6CYA7 | 1 |
| Ketol-acid reductoisomerase (NADP(+)) (KARI) (EC 1.1.1.86) (Acetohydroxy-acid isomeroreductase) (AHIR) (Alpha-keto-beta-hydroxylacyl reductoisomerase) | ilvC B195_04572 | M5QNU9 | 1 |
| Ketol-acid reductoisomerase (NADP(+)) (KARI) (EC 1.1.1.86) (Acetohydroxy-acid isomeroreductase) (AHIR) (Alpha-keto-beta-hydroxylacyl reductoisomerase) (Ketol-acid reductoisomerase type 1) (Ketol-acid reductoisomerase type I) | ilvC A1S_0545 | A3M254 | 1 |
| Ketol-acid reductoisomerase (NADP(+)) (KARI) (EC 1.1.1.86) (Acetohydroxy-acid isomeroreductase) (AHIR) (Alpha-keto-beta-hydroxylacyl reductoisomerase) (Ketol-acid reductoisomerase type 1) (Ketol-acid reductoisomerase type I) | ilvC BSU28290 | P37253 | 1 |
| KHG/KDPG aldolase (EC 4.1.3.16) | eda YPO2067 | Q7CIC5 | 1 |
| KHG/KDPG aldolase [Includes: 4-hydroxy-2-oxoglutarate aldolase (EC 4.1.3.16) (2-keto-4-hydroxyglutarate aldolase) (KHG-aldolase); 2-dehydro-3-deoxy-phosphogluconate aldolase (EC 4.1.2.14) (2-keto-3-deoxy-6-phosphogluconate aldolase) (KDPG-aldolase) (Phospho-2-dehydro-3-deoxygluconate aldolase) (Phospho-2-keto-3-deoxygluconate aldolase)] | eda hga kdgA b1850 JW1839 | P0A955 | 1 |
| Kinase domain protein | KW89_1473 | A0A0K2DWQ0 | 1 |
| Kinase domain protein (EC 2.7.11.-) | KW89_3012 | A0A0K2E1P3 | 1 |
| L,D-transpeptidase | ybiS S0812 SF0769 AJR25_010145 AJR27_020965 | A0A0H2UY71 | 1 |
| L-allo-threonine aldolase (EC 4.1.2.-) | MXAN_1432 | Q1DCD4 | 1 |
| L-arabinose-binding periplasmic protein (ABP) | araF SSON_1217 | Q3Z2S8 | 1 |
| L-asparaginase II (EC 3.5.1.1) | HPAG1_0708 | Q1CTE7 | 1 |
| L-cystine-binding protein tcyA | NMH_2425 | E6N0D0 | 1 |
| L-fucose isomerase (FucIase) (EC 5.3.1.25) (6-deoxy-L-galactose isomerase) | fucI VSAK1_00807 | A6D1C2 | 1 |
| L-fucose-proton symporter (6-deoxy-L-galactose permease) (L-fucose permease) | fucP b2801 JW2772 | P11551 | 1 |
| L-fuculose phosphate aldolase | SPJ_2192 | C1CHG5 | 1 |
| L-glutamate-binding protein / L-aspartate-binding protein | gltI Psyc_0303 | Q4FUY5 | 1 |
| L-lactate dehydrogenase | lldD FTN_0991 | A0Q6L4 | 1 |
| L-lactate dehydrogenase | lldA PA2382 | Q9I197 | 1 |