Synthesis and Characterization of Labeled and PEGylated Peptide.

1. Synthesis and Characterization of Labeled and PEGylated Peptide. Labeled peptide The most commonly encountered labeled peptide are fluorophores and biotin tagged molecules. Depending on the position requirement for the label (e.g. C-terminal, N- terminal) both label types can either be introduced as prelabeled building blocks or through labeling reaction on completed peptide chain. Genosphere Biotechnologies has developed expertise in all labeling approaches to fulfill your requirements. Labeled peptide are most often tagged at the N-terminus or at the amino group of the Lysine side chain. In addition, with suitably selected protecting groups a combined use of different Lysine derivatives within the peptide thus allowing multiple labeling sites per peptide. Biotin labeled peptide Biotin also called vitamin H is a small biologically active molecule with a molecular weight of 244,31 Da. Biotin normally acts as a co-enzyme in living cells. Biotin is widely used in life sciences to label biomolecules in combination with the proteins avidin from egg white or streptavidin from Streptomyces. They both exhibit a high binding affinity towards biotin (KD: 10 - 15 mol/l). Biotin-modified peptides are widely used in various assays. Genosphere Biotechnologies can synthesize your Biotin labeled peptide with labeling on various site of the peptide chain. Biotin may be linked on the N-terminal alpha amine or the side chain epsilon-amine of a lysine at any position on the peptide primary structure. Cysteine thiol labeling is one other option for the introduction of a biotin in the middle of the peptide sequence. PEGylated Peptide Genosphere Biotechnologies provides custom PEGylated peptide production and PEGylation services for research peptides and small molecules. PEGylation is the process of covalently attaching polyethylene glycol (PEG) polymer chains to peptides. PEGylated peptide formation may be achieved through an amide bond on the N- terminal a-amine of the a linear peptide or the side chain e-amine of a Lys included on C-terminal end of the target peptide sequence for example.

2. Other approaches include covalent linkage to a Cys residue via a maleimide thiol reaction intermediary. The use of active peptide in in vivo experiments are sometimes limited by either poor solubility, fast proteolytic degradation, or strong antigenic response. By increasing their molecular mass, PEGylated peptides shows enhanced pharmacokinetics properties. PEGylation has been shown to significantly improve water solubility, biocompatibility, immunogenicity, and other physico-chemical properties. Indeed, the polyethylene glycol polymer with the large amount of hydrogen bound water molecules, acts like a soft shield protecting the attached peptide molecule from proteolytic enzymatic degradation. Moreover, this hydrodynamic bulky structure somewhat masks the potent immunogenic peptide epitopes from the host’s immune system which in turns reduces immunogenicity and antigenicity and thereby limiting adverse immunological effects. In addition it was established that PEGylated peptides are more stable over a range of pH and temperature changes when compared to the non-PEGylated peptide. Genosphere Biotechnologies Address: 52 rue du Moulin de Pierre,92140 Clamart,FRANCE Tel: +33 - 142 717 021 Fax: +33 - 142 717 023 Email: info@genosphere-biotech.com Website: https://www.genosphere-biotech.com/