| PF00013 | KH_1 | KH domain | Q07666 |
| PF00014 | Kunitz_BPTI | Kunitz/Bovine pancreatic trypsin inhibitor domain | P00974 |
| PF00050 | Kazal_1 | Kazal-type serine protease inhibitor domain | P00995 |
| PF00051 | Kringle | Kringle domain | P00734 |
| PF00109 | ketoacyl-synt | Beta-ketoacyl synthase, N-terminal domain | A0A2N9BJK0 |
| PF00197 | Kunitz_legume | Trypsin and protease inhibitor | P83052 |
| PF00225 | Kinesin | Kinesin motor domain | Q02224 |
| PF00467 | KOW | KOW motif | Q06795 |
| PF01344 | Kelch_1 | Kelch motif | Q9Z2X8 |
| PF01352 | KRAB | KRAB box | P35789 |
| PF01450 | KARI_C | Ketol-acid reductoisomerase, C-terminal domain | Q81S27 |
| PF01486 | K-box | K-box region | O22456 |
| PF01500 | Keratin_B2 | Keratin, high sulfur B2 protein | |
| PF02149 | KA1 | Kinase associated domain 1 | Q9P0L2 |
| PF02172 | KIX | KIX domain | Q92793 |
| PF02422 | Keratin | Keratin | |
| PF02524 | KID | KID repeat | |
| PF02669 | KdpC | K+-transporting ATPase, c chain | P03961 |
| PF02702 | KdpD | Osmosensitive K+ channel His kinase sensor domain | Q883V3 |
| PF02705 | K_trans | K+ potassium transporter integral membrane domain | |
| PF02735 | Ku | Ku70/Ku80 beta-barrel domain | P13010 |
| PF02801 | Ketoacyl-synt_C | Beta-ketoacyl synthase, C-terminal domain | A0A2N9BJK0 |
| PF03037 | KMP11 | Kinetoplastid membrane protein 11 | C9ZZD9 |
| PF03520 | KCNQ_channel | KCNQ voltage-gated potassium channel | P51787 |
| PF03521 | Kv2channel | Kv2 voltage-gated K+ channel | |
| PF03618 | Kinase-PPPase | Kinase/pyrophosphorylase | Q195N6 |
| PF03730 | Ku_C | Ku70/Ku80 C-terminal arm | P13010 |
| PF03731 | Ku_N | Ku70/Ku80 N-terminal alpha/beta domain | P13010 |
| PF03790 | KNOX1 | KNOX1 domain | |
| PF03791 | KNOX2 | KNOX2 domain | |
| PF03812 | KdgT | 2-keto-3-deoxygluconate permease | |
| PF03814 | KdpA | Potassium-transporting ATPase A subunit | P03959 |
| PF03882 | KicB | MukF winged-helix domain | A0A0F7LMQ4 |
| PF04383 | KilA-N | KilA-N domain | L7I1M8 |
| PF04579 | Keratin_matx | Keratin, high-sulphur matrix protein | |
| PF04962 | KduI | KduI/IolB family | A0A249DGV6 |
| PF05178 | Kri1 | KRI1-like family | |
| PF05390 | Kre9_KNH1_C | Yeast cell wall synthesis protein KRE9/KNH1 C-terminal | |
| PF05804 | KAP | Kinesin-associated protein (KAP) | |
| PF06178 | KdgM | Oligogalacturonate-specific porin protein (KdgM) | Q934G3 |
| PF06293 | Kdo | Lipopolysaccharide kinase (Kdo/WaaP) family | Q96S44 |
| PF06613 | KorB_C | KorB C-terminal beta-barrel domain | P07674 |
| PF07071 | KDGP_aldolase | KDGP aldolase | Q5E1U2 |
| PF07646 | Kelch_2 | Kelch motif | E3Q9X3 |
| PF07648 | Kazal_2 | Kazal-type serine protease inhibitor domain | Q8C0X7 |
| PF07650 | KH_2 | KH domain | B7MCS9 |
| PF07688 | KaiA | KaiA C-terminal domain | Q79PF6 |
| PF07689 | KaiB | KaiB domain | Q8DMT2 |
| PF07693 | KAP_NTPase | KAP family P-loop domain | A0A0Z8XTP6 |
| PF07765 | KIP1 | KIP1-like protein | |
| PF07827 | KNTase_C | KNTase C-terminal domain | P05057 |
| PF07941 | K_channel_TID | Potassium channel Kv1.4 tandem inactivation domain | P15385 |
| PF07991 | KARI_N | Acetohydroxy acid isomeroreductase, NADPH-binding domain | Q81S27 |
| PF08065 | KI67R | KI67R (NUC007) repeat | |
| PF08433 | KTI12 | Chromatin associated protein KTI12 | G0SHI1 |
| PF08535 | KorB | KorB domain | P07674 |
| PF08552 | Kei1 | Inositolphosphorylceramide synthase subunit Kei1 | |
| PF08568 | Kinetochor_Ybp2 | Uncharacterised protein family, YAP/Alf4/glomulin | Q92990 |
| PF08580 | KAR9 | Yeast cortical protein KAR9 | G0VE12 |
| PF08659 | KR | KR domain | A0A2N9BJK0 |
| PF08785 | Ku_PK_bind | Ku C terminal domain like | P13010 |
| PF08810 | KapB | Kinase associated protein B | Q816F1 |
| PF08872 | KGK | KGK domain | |
| PF09044 | Kp4 | Kp4 | Q90121 |
| PF09303 | KcnmB2_inactiv | KCNMB2, ball and chain domain | Q9Y691 |
| PF09775 | Keratin_assoc | Keratinocyte-associated protein 2 | |
| PF09869 | KH_DUF2096_C | DUF2096 C-terminal KH-like domain | |
| PF10205 | KLRAQ | Predicted coiled-coil domain-containing protein | Q6ZMI0 |
| PF10241 | KxDL | Uncharacterized conserved protein | |
| PF10342 | Kre9_KNH | Kre9/KNH-like N-terminal Ig-like domain | |
| PF10541 | KASH | Nuclear envelope localisation domain | Q6ZMZ3 |
| PF10685 | KGG | Stress-induced bacterial acidophilic repeat motif | |
| PF10937 | Kgd4-YMR31 | Alpha-ketoglutarate dehydrogenase component 4/YMR-31 | |
| PF11004 | Kdo_hydroxy | 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) hydroxylase | B3DUR4 |
| PF11681 | KPP10_Orf10 | Bacteriophage KPP10, Structural protein ORF10 | |
| PF11740 | KfrA_N | Plasmid replication region DNA-binding N-term | |
| PF11759 | KRTAP | Keratin-associated matrix | |
| PF11834 | KHA | KHA, dimerisation domain of potassium ion channel | Q38998 |
| PF11956 | KCNQC3-Ank-G_bd | Ankyrin-G binding motif of KCNQ2-3 | |
| PF12075 | KN_motif | KN motif | |
| PF12309 | KBP_C | KIF-1 binding protein C terminal | Q96EK5 |
| PF12423 | KIF1B | Kinesin protein 1B | G5EFQ4 |
| PF12877 | KIAA1549 | UPF0606 protein KIAA1549 | |
| PF12936 | Kri1_C | KRI1-like family C-terminal | |
| PF13083 | KH_KhpA-B | KhpA/KhpB, KH domain | D0VX24 |
| PF13184 | KH_5 | NusA-like KH domain | P0AFF6 |
| PF13415 | Kelch_3 | Galactose oxidase, central domain | Q9SDM9 |
| PF13418 | Kelch_4 | Galactose oxidase, central domain | Q9Y2U9 |
| PF13619 | KTSC | KTSC domain | A0A7Z7AYG0 |
| PF13723 | Ketoacyl-synt_2 | Beta-ketoacyl synthase, N-terminal domain | A0A0E1PUF7 |
| PF13854 | Kelch_5 | Kelch motif | I7M6H4 |
| PF13885 | Keratin_B2_2 | Keratin, high sulfur B2 protein | |
| PF13925 | Katanin_con80 | con80 domain of Katanin | Q8BG40 |
| PF13964 | Kelch_6 | Kelch motif | |
| PF14089 | KbaA | KinB-signalling pathway activation in sporulation | |
| PF14531 | Kinase-like | Kinase-like | I6ZQR7 |
| PF14611 | KH_SLS1_1 | SLS1 protein first KH domain | |
| PF14662 | KASH_CCD | Coiled-coil region of CCDC155 or KASH | |
| PF14714 | KH_dom-like | KH-domain-like of EngA bacterial GTPase enzymes, C-terminal | C9ZS56 |
| PF14722 | KRAP_IP3R_bind | Ki-ras-induced actin-interacting protein-IP3R-interacting domain | |
| PF15033 | Kinocilin | Kinocilin protein | |
| PF15034 | KRTAP7 | KRTAP type 7 family | |
| PF15152 | Kisspeptin | Kisspeptin | |
| PF15200 | KRTDAP | Keratinocyte differentiation-associated | |
| PF15204 | KKLCAg1 | Kita-kyushu lung cancer antigen 1 | |
| PF15222 | KAR | Kidney androgen-regulated | |
| PF15287 | KRBA1 | KRBA1 family repeat | |
| PF15352 | K1377 | Susceptibility to monomelic amyotrophy | |
| PF15354 | KAAG1 | Kidney-associated antigen 1 | |
| PF15369 | KIAA1328 | Uncharacterised protein KIAA1328 | |
| PF15796 | KELK | KELK-motif containing domain of MRCK Ser/Thr protein kinase | |
| PF15985 | KH_6 | KH domain | P38792 |
| PF16162 | KwaB | Kiwa protein KwaB-like | |
| PF16183 | Kinesin_assoc | Kinesin-associated | A0A0G2K8Z9 |
| PF16197 | KAsynt_C_assoc | Ketoacyl-synthetase C-terminal extension | A0A2N9BJK0 |
| PF16208 | Keratin_2_head | Keratin type II head | |
| PF16210 | Keratin_2_tail | Keratin type II cytoskeletal 1 tail | |
| PF16474 | KIND | Kinase non-catalytic C-lobe domain | Q08AE8 |
| PF16509 | KORA | TrfB plasmid transcriptional repressor | Q6I6B7 |
| PF16642 | KCNQ2_u3 | Unstructured region on Potassium channel subunit alpha KvLQT2 | O43526 |
| PF16767 | KinB_sensor | Sensor domain of alginate biosynthesis sensor protein KinB | Q9HT87 |
| PF16944 | KCH | Fungal potassium channel | |
| PF16987 | KIX_2 | KIX domain | P19659 |
| PF17056 | KRE1 | Killer toxin-resistance protein 1 | |
| PF17097 | Kre28 | Spindle pole body component Kre28 | |
| PF17214 | KH_TffA | Transcription termination factor FttA, KH domain | O50112 |
| PF17383 | kleA_kleC | Uncharacterized KorC regulated protein A | |
| PF17394 | KleE | Uncharacterized KleE stable inheritance protein | |
| PF17818 | KCT2 | Keratinocyte-associated gene product | |
| PF17903 | KH_KRR1_1st | Krr1 KH1 domain | Q99216 |
| PF17904 | KH_9 | FMRP KH0 domain | Q06787 |
| PF17905 | KH_GLD-3_4th | GLD-3 4th KH domain (aka KH5) | Q95ZK7 |
| PF18124 | Kindlin_2_N | Kindlin-2 N-terminal domain | Q86UX7 |
| PF18131 | KN17_SH3 | KN17 SH3-like domain | O60870 |
| PF18176 | KptA_kDCL | KptA in kinetoplastid DICER domain | |
| PF18210 | Knl1_RWD_C | Knl1 RWD C-terminal domain | Q8NG31 |
| PF18434 | Kazal_3 | Kazal-type serine protease inhibitor domain | P10643 |
| PF18758 | KDZ | Kyakuja-Dileera-Zisupton transposase | |
| PF18762 | Kinase-PolyVal | Serine/Threonine/Tyrosine Kinase found in polyvalent proteins | |
| PF18790 | KfrB | KfrB Domain | D5K9G7 |
| PF19258 | KxYKxGKxW_sig | KxYKxGKxW signal peptide | |
| PF19292 | KPBB_C | Phosphorylase b kinase C-terminal domain | |
| PF19298 | KshA_C | 3-Ketosteroid 9alpha-hydroxylase C-terminal domain | F1CMX0 |
| PF19311 | KELAA | KELAA motif | |
| PF19321 | KCTD18_C | BTB/POZ domain-containing protein KCTD18 C-terminus | |
| PF19323 | KCTD4_C | BTB/POZ domain-containing protein KCTD4 C-terminus | |
| PF19329 | KCTD11_21_C | BTB/POZ domain-containing protein KCTD11/21 C-terminus | |
| PF20165 | KBTB_W-LIR | KBTB, W-type LIR motif | Q86V97 |
| PF20704 | KH_NucS_shadow | NucS shadow ORF | |
| PF20777 | KH_SLS1_2 | SLS1 protein second KH domain | |
| PF20871 | KCTD1-15_CTD | BTB/POZ domain-containing protein KCTD1/15, C-terminal domain | |
| PF20883 | Kbp-5 | KNL (Kinetochore null) Binding Protein 5 | |
| PF21122 | KA1_BRSK | BRSK1/2 KA1 domain | |
| PF21126 | KATNA1_MIT | Katanin p60 subunit A1, MIT domain | |
| PF21287 | Kazal_CFAI | Complement factor I, KAZAL domain | |
| PF21288 | Kazal_C6 | Complement component C6, KAZAL domain | |
| PF21322 | KDM6_C-hel | Lysine-specific demethylase 6/UTY, C-terminal helical domain | |
| PF21323 | KDM5_C-hel | Lysine-specific demethylase 5, C-terminal helical domain | |
| PF21326 | KDM6_GATAL | KDM6, GATA-like | |
| PF21330 | Kazal_C7 | Complement component C7, Kazal domain | |
| PF21482 | KH_GLD-3_2nd | GLD-3 2nd KH domain (aka KH3) | |
| PF21506 | Knl-2-like_dom | Kinetochore null protein 2-like domain | |
| PF21714 | KaiA_N | Circadian clock protein KaiA, N-terminal domain | |
| PF21718 | KH_DTX3L | DTX3L, KH-like domain | |
| PF21800 | KH_KRR1_2nd | KRR1 small subunit processome component, second KH domain | |
| PF22352 | K319L-like_PKD | K319L-like, PKD domain | |
| PF22467 | KH_GLD-3_3rd | GLD-3 3rd KH domain (aka KH4) | |
| PF22580 | KYNU_C | Kynureninase C-terminal domain | |
| PF22675 | KH-I_KHDC4-BBP | KHDC4/BBP-like, KH-domain type I | |
| PF22776 | K_trans_C | K+ potassium transporter C-terminal domain | |
| PF22801 | KH_GLD-3_1st | GLD-3 1st KH domain (aka KH2) | |
| PF22891 | KH_PNO1_2nd | Eukaryotic type KH-domain (KH-domain type I) (327.11.2) | |
| PF22923 | KIF2A-like_1st | Kinesin-like protein KIF2A-like, N-terminal | |
| PF22952 | KH_11 | Eukaryotic type KH-domain (KH-domain type I) | |
| PF22985 | KH_BICC1 | Protein bicaudal C homolog 1, KH-like domain | |
| PF23037 | KOWx_SPT5 | Transcription elongation factor SPT5, KOWx domain | |
| PF23038 | KOW6_SPT51-2 | Transcription elongation factor SPT5 homolog 1/2, KOW6 domain | |
| PF23042 | KOW1_SPT5 | Transcription elongation factor SPT5, KOW1 domain | |
| PF23050 | KH_N4BP1_1st | N4BP1, first type I KH-domain | |
| PF23052 | KH_N4BP1_2nd | N4BP1, second type I KH-domain | |
| PF23084 | KH_PARP14_1 | PARP14, first type I KH domain | |
| PF23095 | KH_NusA_C | Transcription termination/antitermination protein NusA, KH domain | |
| PF23154 | KANSL3_1st | KANSL3, helical domain | |
| PF23203 | KIF21A | KIF21A-like domain | |
| PF23204 | KIF21A_2nd | KIF21A-like domain | |
| PF23248 | KH_PARP14_2 | PARP14, second type I KH domain | |
| PF23249 | KH_PARP14_3 | PARP14, third type I KH domain | |
| PF23251 | KH_PARP14_4 | PARP14, fourth type I KH domain | |
| PF23252 | KH_PARP14_5 | PARP14, fifth type I KH domain | |
| PF23253 | KH_PARP14_6 | PARP14, sixth type I KH domain | |
| PF23254 | KH_PARP14_8 | PARP14-like, eighth type I KH domain | |
| PF23284 | KOW2_Spt5 | Transcription elongation factor SPT5, second KOW domain | |
| PF23287 | KOW7_SPT5 | Transcription elongation factor SPT5, seventh KOW domain | |
| PF23288 | KOW6_SPT5 | Transcription elongation factor SPT5, sixth KOW domain | |
| PF23290 | KOW5_SPT5 | Transcription elongation factor SPT5, fifth KOW domain | |
| PF23291 | KOW4_SPT5 | Transcription elongation factor SPT5, fourth KOW domain | |
| PF23450 | KIAA2026_hel | KIAA2026 helical domain | |
| PF23469 | KH_12 | KH-domain | |
| PF23597 | KIAA0319_N | Dyslexia-associated protein KIAA0319 N-terminal domain | |
| PF23620 | KIAA0319 | KIAA0319 C-terminal domain | |
| PF23735 | KIF9 | Kinesin-like protein KIF9 domain | |
| PF23790 | Kyano_Gp96 | Kyanoviridae Gp96 protein | |
| PF24146 | K1-lyase_C | K1 capsule-specific polysaccharide lyase, C-terminal domain | |
| PF24149 | K1-lyase_Rider | K1 capsule-specific polysaccharide lyase, Rider domain | |
| PF24234 | KH_BICC1_1st | BICC1, first type I KH domain | |
| PF24300 | KWL1 | Kiwellin-1 | |
| PF24471 | KH_DEAH11 | DEAH11-like, KH-domain | |
| PF24506 | KNTC1_N | KNTC1, N-terminal | |
| PF24522 | KRIT1_FRMD8_FERM_C | KRIT1/FRMD8, FERM domain C-lobe | |
| PF24563 | KH_Mug60-KHD4 | Mug60/KHD4 KH type I domain | |
| PF24638 | KH_DEAH11_1st | DEAH11 eukaryotic type KH-domain | |
| PF24641 | KH_DEAH11_2nd | DEAH11 eukaryotic type KH-domain | |
| PF24668 | KH_Vigilin | Vigilin KH domain | |
| PF24681 | Kelch_KLHDC2_KLHL20_DRC7 | KLHDC2/KLHL20/DRC7 Kelch-repeats domain | |