A polysialic acid compound is reacted with a hetero-bifunctional reagent to introduce a pendant functional group for site-specific conjugation to sulfhydryl groups, for instance side chains of cysteine units in drugs, drug delivery systems, proteins or peptides. The functional group is, for instance, an N-maleimide group.

A method for producing a site-specifically modified protein based on new carbon-carbon bond formation is disclosed, including the following three steps (marking, activation, and coupling steps): (a) marking of the modification site by incorporating a specific amino acid into a selected position of a target protein; (b) activation of the marked site; and (c) coupling of various post-translational modification (PTM) moieties or other chemical groups onto the activated site to obtain a site-specifically modified protein. The method for producing a site-specifically modified protein can incorporate desired diverse chemical groups including post-translational modification (PTM) moieties into a designated site in a target protein through a new carbon-carbon bond. Furthermore, the modified protein having a site-specific PTM exhibits the same chemical and functional properties as that of a target protein present in cells. Thus, the present invention is useful for studies of cellular proteins, human diseases including cancers and neurodegenerative diseases, and new drug discovery.

The invention provides methods for producing a protein in a cell free protein synthesis system such that the protein does not contain an asparagine (Asn or N) residue at serine (Ser or S) positions. Also provided are compositions and nucleic acid templates for use in the methods described herein.

Compounds, method of making the compounds, and methods of using the compounds to treat Type 2 diabetes and obesity in mammals, including humans. The compounds are dual GLP-1 receptor and GIP receptor agonists in which at least one side chain of a residue in GLP-1 and/or GIP is modified such that the modified GLP-1 and GIP are agonists of both GLP-1 receptor and GIP receptor.

Provided are crystalline , -disubstituted amino acids and their crystalline salts containing a terminal alkene on one of their side chains, as well as optionally crystalline halogenated and deuterated analogs of the , -disubstituted amino acids and their salts; methods of making these, and methods of using these.

The present invention relates to a method for cross-linking peptides using an activated furan-moiety. In particular, the present invention provides a method for cross-linking peptides comprising the steps of: a) providing a composition comprising furan-peptides, said furan-peptides comprising at least one amino acid comprising a furan-moiety; b) contacting said composition comprising furan-peptides with second peptides, thereby obtaining a mixture comprising furan-peptides and second peptides; c) adding an activation signal to said mixture of step b), thereby activating said furan-peptides to activated furan-peptides, and d) reacting said activated furan-peptides with said second peptides, thereby cross-linking said activated furan-peptides with said second peptides.

The present invention provides a method for producing peptides by recombinant means. The peptides are expressed as part of a fusion protein comprising the target peptide and an engineered intein. The invention also provides the engineered inteins, fusion proteins comprising these, and DNA constructs coding for these fusion proteins. Upon thiol-induced cleavage of the fusion protein the carboxy-terminal a-thioester of the target peptide is obtained. The carboxy-terminal -thioester can in principle react with any nucleophile and the strategy therefore allows a wider range of carboxy-terminal modifications such as chemical ligation, bioconjugation, or amidation. The engineered inteins of the present invention are minimized in size and has a cysteine mutation in the position corresponding by alignment to position 3 of Mxe GyrA intein (SEQ ID NO:1) leading to increased expression levels of the fusion protein and higher yields of the isolated target peptide, thus making the method of the invention suitable for production scale.

Novel synthesized amino acids of glutamine and lysine that are directly PEGylated with small, monodisperse PEGs, and a novel process for creating novel amino acid monomers using PEGylation. These amino acids are readily incorporated into peptides for a range of different applications.

The invention features compositions and methods for site-specific modification of proteins by incorporation of an aldehyde tag. Enzymatic modification at a sulfatase motif of the aldehyde tag through action of a formylglycine generating enzyme (FGE) generates a formylglycine (FGly) residue. The aldehyde moiety of FGly residue can be exploited as a chemical handle for site-specific attachment of a moiety of interest to a polypeptide.

Provided are crystalline , -disubstituted amino acids and their crystalline salts containing a terminal alkene on one of their side chains, as well as optionally crystalline halogenated and deuterated analogs of the , -disubstituted amino acids and their salts; methods of making these, and methods of using these.