quartett GmbH has a long-standing experience in the sector of organic-preparative synthesis particularly with regard to peptide-, carbohydrate-, nucleoside chemistry, since the establishment of the production facility in 1995. We are offering synthesis service for various applications. Our highly skilled and committed scientific staff ensures that the most appropriate methods and techniques are selected for every synthesis project. The custom synthesis projects include the production of small compounds like dipeptides up to multi-state synthesis for example protease inhibitors. Custom synthesis can be needed for chemical research purposes, drug discovery, structural studies, reducing the development time of essential agent synthesis by providing the intermediate stages.

If you are involved in structural studies or drug discovery quartett offers you exceptional quality peptide libraries with an excellent cost benefit ratio. In the meantime quartett has become a reliable and well-known supplier for research departments in universities, chemical industry, pharmaceutical and cosmetic research departments.

Our service starts with your completion of the request form. Beyond this point our experienced scientists will accompany you through the complete process starting with a prompt and personal consultation. We are very exacting about quick order processing connected with fast turnaround times of the complete synthesis project. The enormous quality of our products is being ensured by reliable quality control using state-of-the-art techniques, as HPLC, TLC, NMR, elementary analysis, everything offered to a competitive price. In our well-equipped laboratories in two independent production sites we are able to synthesis from milligram up to kilogram scale.

Extract of our service program:

Custom Peptide Synthesis
- Manual and automatic solid phase peptide synthesis (SPPS) following the Fmoc strategy up to 30 amino acids using state of the art derivatives and additives if necessary (e.g. Hmb backbone amide protective group); longer peptides on special request
- Peptide synthesis in solution until eight amino acids from 100 mg to 100 g
- Solid phase fragment condensation
- Custom synthesis of highly purified peptides (HPLC purity > 80 % and > 95 %) for enzymology or biological activity studies:
quartett offers peptides with a purity (HPLC, MS) > 80 % as well as > 95 % useful for enzymology or biological activity studies ranging from 2 mg up to several grams (on request). In general, delivery time for standard peptides with > 80 % purity is about 2 weeks and for peptides with > 95 % purity is approx. 3 weeks after receipt of official order. All peptides are controlled by HPLC-MS and supplied with documentation. For further services, such as modifications (phospho- or glycopeptides, FITC- or biotinlabeled peptides, cyclic peptides), other purities, lenghts or amounts, we will provide you with a quotation according to your specifications.
- Custom synthesis of peptides with immunograde purity > 70 % for immunological and related purposes (e.g. ELISA testing, antibody production):
Careful preparation and choice of antigen is most important for your antibody production project. In addition, the quality of the choosen peptide correlates directly with the quality of raising antibodies. quartett is pleased to provide you with high quality peptides as well as antibody production services itself. Coupling peptides to standard carrier proteins with higher mass (KLH or BSA) is also possible which ensures maximum antigenicity as degradation by the host animal is decreased. Our peptide services are seperately available as well as in combination with antibody production services. In general, delivery time for standard peptides with > 70 % purity is about 2 weeks after receipt of official order. All peptides are controlled by HPLC-MS and supplied with documentation.
- Custom synthesis of peptide libraries in units of 1 - 2 mg in 96 well microplates with a purity > 70 %

Modification and Derivatization of Peptides
- Acetylation
- Synthesis of peptide aldehydes
- Synthesis of amides
- Synthesis of peptide thioesters (e.g. use in native chemical ligation)
- Synthesis of protease inhibitors
- Synthesis of O-linked and N-linked glycopeptides (e.g. O-glycosyl-Ser and N-glycosyl-Asn)
- Synthesis and implementation of Fmoc-Asn (Ac3GlcNAc)-OH and variants as a model for glycopeptides
- [3+2]-cycloaddition of alkinylpeptides to sugarazides ("click-reaction") resulting in neoglycoproteins
- Phosphorylation
- Biotin-labeling of peptides
- Glycosylation of peptides
- Integration of D-Amino acids
- Integration of beta-amino acids
- Integration of other non-proteinogenic amino acids (e.g. propargylglycine)
- Coupling of peptides to proteins
- Coupling of peptides to enzymes
- Implementation of spacers for peptide conjugates
- Fluorescein-labeled peptides

Isolation and Purification of Peptides
- Chromatography (preparative HPLC, column chromatography)
- Development of methods for isolation and purification of pharmaceutically relevated compounds

Peptide Libraries
For many scientific studies a large number of peptides in very small amounts is required. Peptide libraries are an important tool for proteomics. quartett offers simultanously synthesis of 864 defined single peptides for the construction of peptide libraries. Possible applications are:

- Epitope mapping of antibodies, B- and T-cell epitope mapping
- Screening purposes
- Identification of drug candidates
- Protein-protein interaction analyses
- Determination of structure-function relationships within proteins

- 96 well format, each well contains one individual lyophilized peptide
- 1 - 2 mg, 4 - 30 amino acids
- HPLC purity > 70 %
- All modifications and non natural building blocks are possible

Sugar Amino Acids (SAAs)
- Synthesis of pyranoid and furanoid carbohydrate building blocks containing at least one carboxyl- and
  amino group
- Synthesis of linear and cyclic homo- and hetero oligomers containing SAAs
- SAAs as turn as well as peptide mimetics
- SAAs as carbohydrate mimetics
- SAAs as scaffolds
- Backbone or sidechain modification of cyclic peptides containing SAAs
- Incorporation of SAAs in biological active peptides
- Synthesis of cyclodextrin mimetics

- Synthesis of complex carbohydrate building blocks
- Synthesis of inhibitors (e.g. glycosidase inhibitors)
- Synthesis of protected and unprotected O,N,S-glycosides
- Synthesis of C-glycosides
- Synthesis of glycosyl acceptors and donors for O,S-glycosylation
- O- and C-alkylation reactions
- Coupling of carbohydrates (e.g. desoxyhalo) to aromatic compounds
- 1,4-addition (e.g. Michael condensation reaction)
- Preparation of phosphates and phosphonates
- Building blocks for O-glycopeptides (e.g. N-Fmoc-O-(Ac3-a-D-GalNAc)-L-Ser-OH)
- Building blocks for N-glycopeptides (e.g. 2-N-Fmoc-4-N-(Ac3-b-D-GlcNAc)-L-Asn-OH)
- Optimization of methods for glycosylation
- Carbohydrates as scaffolds

- Individual modification of nucleobases
- Selective modification of sugar residues
- Modified nucleosides as substrate analogues for kinases