FAQs
Technical
- What are pseudoproline amino acids and what advantage do they have in peptide synthesis?
- What are the typical contaminants associated with peptide synthesis?
- What is the difference between peptide purity and peptide yield?
- What are the typical salts associated with my peptide?
- If I have biotin in my peptide, do I need a spacer between the biotin group and the peptide sequence and if so which spacer should I use?
- What can I do to increase the cell permeability of a peptide?
- How do I solubilize my peptides?
- How do I characterize batches of my "drug candidate" peptide, which contains a D-amino acid?
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How do you calculate hydrophobicity?
The hydrophobicity algorithm used is from Fauchere & Pliska (1983), Eur J Med Chem 10:369. The parameters for the amino acids are shown below. Peptide endings are also taken into account in calculating the hydrophobicity value. "Hydrophobicity" varies between approximately -1 (most hydrophilic) and +2 (most hydrophobic). A second hydrophobicity parameter, "Hydro-2", is calculated as the criterion "percentage of hydrophobic residues".
ID Amino Acid Charge Hydro Mwt 1 A Ala L-Alanine 0 0.310 71.08 2 C Cys L-Cysteine 0 1.540 103.14 3 D Asp L-Aspartic acid -1 -0.770 115.09 4 E Glu L-Glutamic acid -1 -0.640 129.12 5 F Phe L-Phenylalanine 0 1.790 147.18 6 G Gly Glycine 0 0.000 57.05 7 H His L-Histidine 1 0.130 137.14 8 I Ile L-Isoleucine 0 1.800 113.16 9 K Lys L-Lysine 1 -0.990 128.17 10 L Leu L-Leucine 0 1.700 113.16 11 M Met L-Methionine 0 1.230 131.20 12 N Asn L-Asparagine 0 -0.600 114.10 13 P Pro L-Proline 0 0.720 97.12 14 Q Gln L-Glutamine 0 -0.220 128.13 15 R Arg L-Arginine 1 -1.010 156.19 16 S Ser L-Serine 0 -0.04 87.08 17 T Thr L-Threonine 0 0.26 101.11 18 V Val L-Valine 0 1.22 99.13 19 W Trp L-Tryptophan 0 2.25 186.22 20 Y Tyr L-Tyrosine 0 0.96 163.18