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  cRAP protein sequences

The common Repository of Adventitious Proteins, cRAP (pronounced "cee-RAP"), is an attempt to create a list of proteins commonly found in proteomics experiments that are present either by accident or through unavoidable contamination of protein samples. The types of proteins included fall into three general classes:

  1. common laboratory proteins;
  2. proteins added by accident through dust or physical contact; and
  3. proteins used as molecular weight or mass spectrometry quantitation standards.

Version 1.0 of cRAP was based on NCBI protein sequence entries, drawn from "nr". The current version (2012.01.01) was based on UNIPROT protein sequence entries. This change was made to take advantage of the higher information content in the curated entries in the UNIPROT-knowledgebase.

This list is based on an analysis of the current version of GPMDB, as well as suggestions by users. If you would like to have other proteins included in this list, please contact us by email with your suggestions.

The current version of cRAP in FASTA format can be obtained from the GPM FTP site, using the URL

1. Laboratory proteins:

Id Description Reason
1. ALBU_BOVIN (P02769) Serum albumin precursor (Allergen Bos d 6) (BSA) Reagent and lab contaminant
2. CTRA_BOVIN (P00766) Chymotrypsinogen A (EC [Contains: Chymotrypsin A chain A; Chymotrypsin A chain B; Chymotrypsin A chain C] Reagent
3. CTRB_BOVIN (P00767) Chymotrypsinogen B (EC [Contains: Chymotrypsin B chain A; Chymotrypsin B chain B; Chymotrypsin B chain C] Reagent
4. LALBA_BOVIN (P00711) Alpha-lactalbumin precursor (Lactose synthase B protein) (Allergen Bos d 4) Reagent and lab contaminant
5. LYSC_LYSEN (Q7M135) Lysyl endopeptidase (EC (Lys-C) Reagent
6. PEPA_BOVIN (P00792) Pepsin A precursor (EC Reagent
7. PEPA_PIG (P00791) Pepsin A precursor (EC Reagent
8. PEPB_PIG (Q10735) Pepsin B precursor (EC (Parapepsin I) (Fragment) Reagent
9. PEPC_PIG (P30879) Gastricsin precursor (EC (Pepsinogen C) (Fragment) Reagent
10. SSPA_STAAU (P04188) Glutamyl endopeptidase precursor (EC (Staphylococcal serine proteinase) (V8 protease) (V8 proteinase) (Endoproteinase Glu-C) Reagent
11. TRY1_BOVIN (P00760) Cationic trypsin precursor (EC (Beta-trypsin) [Contains: Alpha-trypsin chain 1; Alpha-trypsin chain 2] (Fragment) Reagent
12. TRY2_BOVIN (Q29463) Anionic trypsin precursor (EC Reagent
13. TRYP_PIG (P00761) Trypsin precursor (EC Reagent
14. CAS1_BOVIN (P02662) Alpha-S1-casein precursor Reagent and lab contaminant
15. CAS2_BOVIN (P02663) Alpha-S2-casein precursor [Contains: Casocidin-1 (Casocidin-I)] Reagent and lab contaminant
16. CASB_BOVIN (P02666) Beta-casein precursor Reagent and lab contaminant
17. CASK_BOVIN (P02668) Kappa-casein precursor [Contains: Casoxin C; Casoxin 6; Casoxin A; Casoxin B; Casoplatelin] Reagent and lab contaminant
18. GFP_AEQVI (P42212) Aequorea victoria Green fluorescent protein Reagent
19. PLMP_GRIFR (P81054) Peptidyl-Lys metalloendopeptidase precursor - Grifola frondosa (LysN) Reagent

2. Dust/contact proteins:

Id Description Reason
1. AMYS_HUMAN (P04745) Salivary alpha-amylase precursor (EC (1,4-alpha-D-glucan glucanohydrolase) Human saliva
2. K1C10_HUMAN (P13645) Keratin, type I cytoskeletal 10 (Cytokeratin-10) (CK-10) (Keratin-10) (K10) Human skin
3. K1C9_HUMAN (P35527) Keratin, type I cytoskeletal 9 (Cytokeratin-9) (CK-9) (Keratin-9) (K9) Human skin
4. K2C1_HUMAN (P04264) Keratin, type II cytoskeletal 1 (Cytokeratin-1) (CK-1) (Keratin-1) (K1) (67 kDa cytokeratin) (Hair alpha protein) Human skin
5. K22E_HUMAN (P35908) Keratin, type II cytoskeletal 2 epidermal (Cytokeratin-2e) (K2e) (CK 2e) Human skin
6. K1H1_HUMAN (Q15323) Keratin, type I cuticular Ha1 (Hair keratin, type I Ha1) Human hair
7. K1H2_HUMAN (Q14532) Keratin, type I cuticular Ha2 (Hair keratin, type I Ha2) Human hair
8. K1H4_HUMAN (O76011) Keratin, type I cuticular Ha4 (Hair keratin, type I Ha4) Human hair
9. K1H5_HUMAN (Q92764) Keratin, type I cuticular Ha5 (Hair keratin, type I Ha5) Human hair
10. K1H6_HUMAN (O76013) Keratin, type I cuticular Ha6 (Hair keratin, type I Ha6) Human hair
11. K1H7_HUMAN (O76014) Keratin, type I cuticular Ha7 (Hair keratin, type I Ha7) Human hair
12. K1H8_HUMAN (O76015) Keratin, type I cuticular Ha8 (Hair keratin, type I Ha8) Human hair
13. K1HA_HUMAN (O76009) Keratin, type I cuticular Ha3-I (Hair keratin, type I Ha3-I) Human hair
14. K1HB_HUMAN (Q14525) Keratin, type I cuticular Ha3-II (Hair keratin, type I Ha3-II) Human hair
15. KRHB1_HUMAN (Q14533) Keratin, type II cuticular Hb1 (Hair keratin, type II Hb1) (ghHKb1) (ghHb1) (MLN 137) Human hair
16. KRHB2_HUMAN (Q9NSB4) Keratin, type II cuticular Hb2 (Hair keratin, type II Hb2) Human hair
17. KRHB3_HUMAN (P78385) Keratin, type II cuticular Hb3 (Hair keratin, type II Hb3) Human hair
18. KRHB4_HUMAN (Q9NSB2) Keratin, type II cuticular Hb4 (Hair keratin, type II Hb4) Human hair
19. KRHB5_HUMAN (P78386) Keratin, type II cuticular Hb5 (Hair keratin, type II Hb5) Human hair
20. KRHB6_HUMAN (O43790) Keratin, type II cuticular Hb6 (Hair keratin, type II Hb6) (ghHb6) Human hair
21. K1C15_SHEEP (O77727) Keratin, type I cytoskeletal 15 (Cytokeratin-15) (CK-15) (Keratin-15) (K15) Sheep wool
22. K1M1_SHEEP (P02534) Keratin, type I microfibrillar 48 kDa, component 8C-1 (Low-sulfur keratin) Sheep wool
23. K1M2_SHEEP (P25690) Keratin, type I microfibrillar, 47.6 kDa (Low-sulfur keratin) Sheep wool
24. K2M1_SHEEP (P02539) Keratin, type II microfibrillar (Low-sulfur keratin) (Fragment) Sheep wool
25. K2M2_SHEEP (P15241) Keratin, type II microfibrillar, component 7C Sheep wool
26. K2M3_SHEEP (P25691) Keratin, type II microfibrillar, component 5 Sheep wool
27. KRA33_SHEEP (P02444) Keratin, high sulfur matrix protein, IIIB3 Sheep wool
28. KRA34_SHEEP (P02445) Keratin, high sulfur matrix protein, IIIB4 Sheep wool
29. KRA3A_SHEEP (P02443) Keratin, high-sulfur matrix protein, IIIA3A Sheep wool
30. KRA3_SHEEP (P02441) Keratin, high-sulfur matrix protein, IIIA3 Sheep wool
31. KRA61_SHEEP (Q02958) Keratin, glycine/tyrosine-rich of hair Sheep wool
32. KRB2A_SHEEP (P02438) Keratin, high-sulfur matrix protein, B2A Sheep wool
33. KRB2B_SHEEP (P02439) Keratin, high-sulfur matrix protein, B2B Sheep wool
34. KRB2C_SHEEP (P02440) Keratin, high-sulfur matrix protein, B2C Sheep wool
35. KRB2D_SHEEP (P08131) Keratin, high-sulfur matrix protein, B2D Sheep wool
36. KRUC_SHEEP (P26372) Keratin, ultra high-sulfur matrix protein (UHS keratin) Sheep wool
37. SRPP_HEVBR (O82803) Small rubber particle protein - Hevea brasiliensis Latex gloves
38. REF_HEVBR (P15252) Rubber elongation factor protein - Hevea brasiliensis Latex gloves

3. Molecular weight markers/Standard proteins:

Id Description Reason
1. CYC_HORSE (P00004) Horse heart cytochrome C Molecular weight marker/mass spec. standard
2. CAH2_BOVIN (P00921) Bovine carbonic anhydrase 2 (EC Molecular weight marker
3. ADH1_YEAST (P00330) Yeast alcohol dehydrogenase 1 Molecular weight marker
4. ALDOA_RABIT (P00883) Rabbit fructose-bisphosphate aldolase A Molecular weight marker
5. LYSC_CHICK (P00698) Hen egg lysozyme C precursor Molecular weight marker/mass spec. standard
6. MYG_HORSE (P68082) Horse heart myoglobin Molecular weight marker/mass spec. standard
7. OVAL_CHICK (P01012) Hen egg ovalbumin Molecular weight marker
8. BGAL_ECOLI (P00722) E. coli beta-galactosidase (E.C. Molecular weight marker
9. DHE3_BOVIN (P00366) Bovine glutamate dehydrogenase 1, mitochondrial precursor (E.C. Molecular weight marker

4. Sigma-Aldrich Universal Protein Standard:

Id Description Reason
1. ALBU_HUMAN (P02768) Serum albumin 66,393 Recombinant Pichia pastoris UPS
2. ANT3_HUMAN (P01008) Antithrombin-III 49,033 Plasma Glycosylation UPS
3. ANXA5_HUMAN (P08758) Annexin A5 35,782 Placenta Acetylation UPS
4. B2MG_HUMAN (P61769) Beta-2-microglobulin 11,729 Urine UPS
5. BID_HUMAN (P55957) BH3 interacting domain death agonist [BID] 21,978 Recombinant E. coli UPS
6. CAH1_HUMAN (P00915) Carbonic anhydrase 1 28,738 Erythrocytes Acetylation UPS
7. CAH2_HUMAN (P00918) Carbonic anhydrase 2 29,095 Erythrocytes Acetylation UPS
8. CATA_HUMAN (P04040) Catalase 59,583 Erythrocytes UPS
9. CATD_HUMAN (P07339) Cathepsin D 26,624 Liver Glycosylation UPS
10. CATG_HUMAN (P08311) Cathepsin G 26,751 Sputum Glycosylation UPS
11. CO5_HUMAN (P01031) Complement C5 [Complement C5a] 8,266 Recombinant E. coli UPS
12. CRP_HUMAN (P02741) C-reactive protein 23,030 Plasma UPS
13. CYB5_HUMAN (P00167) Cytochrome b5 16,021 Recombinant E. coli 6-His UPS
14. CYC_HUMAN (P99999) Cytochrome c [Apocytochrome c] 11,608 Recombinant E. coli UPS
15. EGF_HUMAN (P01133) Epidermal growth factor 6,211 Recombinant E. coli UPS
16. FABPH_HUMAN (P05413) Fatty acid-binding protein 14,716 Plasma Acetylation,Phosphorylation UPS
17. GELS_HUMAN (P06396) Gelsolin 82,954 Plasma Phosphorylation UPS
18. GSTA1_HUMAN (P08263) Glutathione S-transferase A1 [GST A1-1] 25,482 Recombinant E. coli UPS
19. GSTP1_HUMAN (P09211) Glutathione S-transferase P [GST] 23,220 Placenta UPS
20. HBA_HUMAN (P69905) Hemoglobin alpha chain 15,127 Erythrocytes UPS
21. HBB_HUMAN (P68871) Hemoglobin beta chain 15,867 Erythrocytes,Acetylation,Nitrosylation,Glycosylation UPS
22. IGF2_HUMAN (P01344) Insulin-like growth factor II 7,464 Recombinant E. coli UPS
23. IL8_HUMAN (P10145) Interleukin-8 8,381 Recombinant E. coli UPS
24. KCRM_HUMAN (P06732) Creatine kinase M-type [CK-MM] 43,070 Heart UPS
25. LALBA_HUMAN (P00709) Alpha-lactalbumin 14,070 Milk Glycosylation UPS
26. LEP_HUMAN (P41159) Leptin 16,024 Recombinant E. coli UPS
27. LYSC_HUMAN (P61626) Lysozyme C 14,692 Milk UPS
28. MYG_HUMAN (P02144) Myoglobin 17,051 Heart UPS
29. NEDD8_HUMAN (Q15843) Neddylin [Nedd8] 9,071 Recombinant E. coli UPS
30. NQO1_HUMAN (P15559) NAD(P)H dehydrogenase [quinone] 1[DT Diaphorase] 30,984 Recombinant E. coli UPS
31. NQO2_HUMAN (P16083) Ribosyldihydronicotinamide dehydrogenase(quinone) [Quinone oxidoreductase 2 or NQO2] 25,817 Recombinant E. coli UPS
32. PDGFB_HUMAN (P01127) Platelet-derived growth factor B chain 12,286 Recombinant E. coli UPS
33. PPIA_HUMAN (P62937) Peptidyl-prolyl cis-trans isomerase A [Cyclophilin A] 17,947 Recombinant E. coli UPS
34. PRDX1_HUMAN (Q06830) Peroxiredoxin 1 22,106 Recombinant E. coli UPS
35. RASH_HUMAN (P01112) GTPase HRas [Ras protein] 21,292 Recombinant E. coli UPS
36. RETBP_HUMAN (P02753) Retinol-binding protein 21,065 Urine UPS
37. SODC_HUMAN (P00441) Superoxide dismutase [Cu-Zn] 15,800 Erythrocytes Acetylation UPS
38. SUMO1_HUMAN (P63165) Small ubiquitin-related modifier 1 [SUMO-1] 37,420 Recombinant E. coli GST UPS
39. SYH_HUMAN (P12081) Histidyl-tRNA synthetase [Jo-1] 58,223 Recombinant E. coli UPS
40. TAU_HUMAN (P10636) Microtubule-associated protein tau [Tau protein] 46,810 Recombinant E. coli 6-His UPS
41. THIO_HUMAN (P10599) Thioredoxin 12,424 Recombinant E. coli 6-His UPS
42. TNFA_HUMAN (P01375) Tumor necrosis factor [TNF-alpha] 17,350 Recombinant E. coli UPS
43. TRFE_HUMAN (P02787) Serotransferrin [Apotransferrin] 75,143 Plasma Glycosylation UPS
44. TRFL_HUMAN (P02788) Lactotransferrin 78,289 Milk Glycosylation UPS
45. UB2E1_HUMAN (P51965) Ubiquitin-conjugating enzyme E2 E1 [UbcH6] UPS
46. UBE2C_HUMAN (O00762) Ubiquitin-conjugating enzyme E2 C [UbcH10] 20,473 Recombinant E. coli 6-His UPS
47. UBE2I_HUMAN (P63279) Ubiquitin-conjugating enzyme E2 I [UbcH9] 22,907 Recombinant E. coli UPS
48. RS27A_HUMAN (P62979) Ubiquitin-40S ribosomal protein S27a 9,387 Recombinant E. coli 6-His UPS

5. Common viral contaminants:

Id Description Reason
1. GAG_SCVLA (P32503) Major coat protein, Saccharomyces cerevisiae virus L-A (ScV-L-A) (ScVL1) virus infects yeast cultures
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