Peptide name pI Sequence and predicted secondary structure* Heparan sulfate binding region Internalization mechanism Ref. Viral protein-derived CPP 1 TAT peptide (49–57) pI: 12.70 RKKRRQRRR CCCCCCCCC RKKRRQRR Lipid raft-mediated macropinocytosis [25 , 26 ] 2 Nucleoplasmin NLS (155–170) pI: 11.47 KRPAAIKKAGQAKKKK CcHHHHHHHhHHHhCCNot reported Not reported [58 ] 3 HTLV-II Rex (4–16) pI: 12.85 TRRQRTRRARRNR CCCCHHHHCCCCC TRRQRT Direct translocation [21 , 22 ] 4 Lambda-N (48–62) pI: 11.83 QTRRRERRAEKQAQW CCHHHHHHHHHHCCC RRRERR Not reported [22 ] 5 Phi21 N (12–29) pI: 11.45 TAKTRYKARRAELIAERR CCCCCCCHHHHHHHHHHH KTRYKARRA Not reported [22 ] 6 Delta N (1–22) pI: 11.44 MDAQTRRRERRAEKQAQWKAAN CCCCHHHHHHHHHHHHHHHHHH TRRRERRA Not reported [22 ] 7 FHV coat (35–49) pI: 13.00 RRRRNRTRRNRRRVR CCCCCCCCCCCCCCC RRRRNRTRRNRRRVR Not reported 8 BMV coat (8–26) pI: 12.78 KMTRAQRRAAARRNRWTAR CcCHHHHHHHHHHhccccCARRNRW Not reported 9 HIV-1 Rev (35–46) pI: 12.85 RQARRNRRRRWR CCCCCCCHHHHH RQARRNRRRRWR Not reported [22 ] 10 Rev (26–42) pI: 12.54 TRQARRNRRRRWRERQF CCCCCCCCHHHHHHHHH TRQARRNRRRRWRERQF Energy dependent lipid raft-mediated macropinocytosis [27 , 28 ] 11 CPP from pestivirus envelope glycoprotein (Erns) (194–220) pI: 11.72 ENARQGAARVTSWLGRQLRIAGKRLEGRSKTWFGAYA CCCccchHHHHHHHHHHHHHHHHhhhCCCCccccccCBasic residues Direct translocation [23 ] 12 gp41 fusion sequence pI: 11.33 GALFLGWLGAAGSTMGAWSQPKKKRKV HHHHHHHHHHHHHHHHHCCCCCCCCCC WSQPKKKRKV Direct translocation [24 ] 13 VP22 pI: 12.10 DAATATRGRSAASRPTERPRAPARSASRPRRPVD CCCccCCCCCCCCCCCCCCCCCCCCCCCCCCCCCSRPRRP Energy dependent lipid raft-mediated macropinocytosis [27 , 29 ] 14 SV40 NLS pI: 11.33 PKKKRKV CCCCCCCPKKKRKV Not reported [59 , 60 ] Animal homeostatic modulator-derived CPP 15 Penetratin pI: 12.31 RQIKIWFQNRRMKWKK CCCHHHHHHHCCCCCC NRRMKW Direct translocation Endocytosis [61 ] 16 CPPecp pI: 10.05 NYRWRCKNQN CCCCCCCCCC RWRCK Macropinocytosis [12 , 62 ] 17 Apolipoprotein B binding domain pI: 9.82 SVKAQYKKNSDKHRLMRKRGLK CCcccccCCCCCCCCCCcCCCCBasic residues Endocytosis [63 , 64 ] 18 hCT (9 32) pI: 6.74 LGTYTQDFNKFHTFPQTAIGVGAP HHHHHHHHHHHHHHCHHHHHCCCC Not reported Endocytosis [63 , 65 ] 19 pVEC (615–632) pI: 12.48 LLIILRRRIRKQAHAHSK ChhHHHHHHHHHHHhcCCLRRRIRK Macropinocytosis and clathrin mediated endocytosis [66 –68 ] 20 hLF peptide pI: 10.93 KCFQWQRNMRKVRGPPVSCIKR CCCchhHHHHhCCCCCcececCMRKVRG Lipid raft-mediated endocytosis [69 ] 21 PDX-1-PTD pI: 12.31 RHIKIWFQNRRMKWKK ChhhhHhhhhhhhhcCNRRMKWKK Caveolae-dependent endocytosis and lipid raft-mediated macropinocytosis [70 ] Antimicrobial peptide 22 LL-37 (1–37) pI: 10.61 LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHCCCCC FRKSKEKI Endocytosis [30 , 31 , 71 ] 23 SynB1 (1–18) pI: 12.30 RGGRLSYSRRRFSTSTGR CCCCEEEEECCEEEEECC Basic residues Endocytosis [32 ] 24 SynB3 pI: 12.18 RRLSYSRRRF CCCCcccCCCBasic residues Endocytosis [32 ] Toxin-derived CPP 25 bPrPp (1–28) pI: 10.03 MVKSKIGSWILVLFVAMWSDVGLCKKRP CCCCCCCCHHHHHHHHHHHHHHHCCCC Basic residues Macropinocytosis [33 ] 26 Crotamine (1–42) pI: 9.51 YKQCHKKGGHCFPKEKICLPPSSDFGKMDCRWRWKCCKKGSG CCHHHHHCEEEECCCCCCCCCCCEECCCCCCCCCEEEECCCC RWRWK Endocytosis [34 ] 27 Maurocalcine (MCa) (1–33) pI: 9.46 GDCLPHLKLCKENKDCCSKKCKRRGTNIEKRCR CCCCCCCCCCCCHHHCCCCEEECCCCCCCCEEE SKKCKR and EKRCR Macropinocytosis [35 , 36 ]