Peptide synthesis Quantities routinely supplied are 10mg, 25mg, 50mg and 100mg at one of two purity levels (≥80% and ≥95%), with absolute values dependent upon the number of amino acid residues, sequence complexity and overall amino acid composition. Peptides are normally supplied with free N-terminal amino and C-terminal acid groups but modifications such as N-terminal acetylation or C-terminal amidation, are available at no extra charge.  Possible modifications available include: Incorporation of D-amino acids Termini/side chain modifications (e.g DNP, FAM, TAMRA, biotin, long chain alkanes, para-nitroanilides, AMC, etc.). Side chain modifications (e.g  phosphorylation of serine, threonine or tyrosine, or sulphation of tyrosine). Cyclisation via disulphide bond formation or by formation of cyclic amides Also available: phosphopeptides, acetylated peptides, multiple antigen peptides and peptide panels. Peptide purification and analysis In the majority of cases, peptides are purified to the required specification by techniques including reversed-phase and ion exchange high performance liquid chromatography (hplc). High purity peptides (≥95%) are prepared by the most appropriate route for the structure and quantity required, and undergo rigorous purification prior to dispatch. Lower purity (≥80%) peptides are prepared by analogous methods but are subjected to slightly less rigorous purification procedures. Nevertheless, the purity of these lower specification products is often in excess of 90%, although this cannot be guaranteed. Peptide purity is assessed by reversed phase and, additionally, in some cases, by cation exchange high performance liquid chromatography and is stated as the percentage of the total peak area of the major peak. Additionally, all peptides are subjected to mass spectrometric analysis as a routine part of BIOMOL’s service in order to ensure confidence in the integrity of the product supplied. A copy of the analytical chromatogram and mass spectroscopic data is included in the datasheet that accompanies each product.  Amino acid analysis is not carried out as part of any routine service, save for MAP characterisation, but is available upon request, at an extra charge, for both amino acid ratio confirmation and net peptide content determination. Peptide content (as may be determined by amino acid analysis) will normally exceed 70%; however, no minimum percentage of residual salts can be specified since counter ions to charged functionalities within individual peptides make this highly sequence-dependent. Peptide conjugation For peptide-based immunisation procedures, the use of peptide-carrier protein conjugates is recommended other than in studies where the MAP approach is being used.  Keyhole limpet haemocyanin (KLH) is routinely used as a carrier protein, with conjugation of the peptide to the carrier protein being effected via an N-terminal cysteinyl or C-terminal cysteinyl amide residue (natural or added), using an MBS-mediated optimised coupling procedure.  Other carrier proteins (e.g. BSA, ovalbumin, thyroglobulin, tetanus toxoid, diphtheria toxoid, tuberculin PPD) and conjugation procedures (e.g. glutaraldehyde, bis-diazotised tolidine (BDT), carbodiimide) are available upon request. Protein modification BIOMOL has considerable experience of the preparation of matrices for specific immunopurification and immunodepletion, and in the immobilisation of enzymes for continuous flow applications where retention of a protein’s chemical and physical integrity is essential for subsequent activity. Please contact BIOMOL Technical Support for additional information and assistance.