The present invention relates to a cyclic peptide from a novel bone morphogenetic protein 2 (BMP2), a preparation method therefor and an application thereof. The cyclic peptide from the novel BMP2 is selected from one of the following cyclized polypeptides: 1. a cyclized polypeptide having the sequence of CKIPKASSVPTELSAISMLYLGPGGDWIVAC; and 2. a cyclized polypeptide of which the sequence has an 80% homology with the sequence defined in item 1. The present invention also relates to a preparation method for the cyclic peptide from the novel BMP2, and an application thereof in the preparation of the composite material for promoting the repair of large-sized bone defects.

The invention provides improved methods of conjugating an agent to a thiol moiety in a protein that contains at least one disulfide bond and at least one trisulfide bond. Exemplary embodiments include the production of antibody drug conjugates substantially free of impurities created in the presence of reactive sulfide moieties in the production processes.

Provided herein are methods for refolding denatured protein (e.g., from inclusion bodies) that do not require the use of a denaturing agent. Exemplary methods use a high pH for solubilizing denatured protein, followed by a decrease in pH for refolding the proteins.

Methodology was developed for transformation of methionine residues into homocysteine derivatives. Methionine residues can undergo alkylation reactions at low pH to yield sulfonium ions, which can then be selectively demethylated to give alkyl homocysteine residues. This process tolerates many functional groups.

Methods of producing an aqueous formulation of an antigen-binding protein or enhancing re-oxidation of an antigen-binding protein are disclosed. The methods comprise (a) contacting an aqueous solution comprising antigen-binding protein molecules with a charged depth filter under conditions sufficient to enhance re-oxidation of the antigen-binding protein molecules and achieve a decrease in the percentage of reduced antigen-binding protein molecules, compared to the percentage of reduced anti-gen-binding protein molecules observed prior to step (a); and (b) optionally, measuring the amount or relative amount of reduced an¬tigen-binding protein molecules. Formulations comprising a re-oxidized antigen-binding protein are also described.

The present invention relates to the use of sulfocysteine and derivatives thereof as cell culture additives to reduce the trisulfide levels in proteins produced in cell culture.

The present invention provides method of increasing the percentage of monomer in a composition of recombinantly expressed antibody molecules characterised in that the antibody molecule comprises at least one Fv with specificity for an antigen of interest comprising one VH and one VL wherein said VH and VL are connected directly or indirectly via one or more linkers and are stabilised by a disulfide bond therebetween, said method comprises: a) a conversion step of treating the composition with a denaturant selected from urea and/or Guanidine hydrochloride; b) wherein step a) is performed in the presence of a reducing agent or after treatment with a reducing agent.

The present invention relates to a method for preparing a compound T having a thioether group from a compound D having a disulfide group in the presence of a carbene.

Provided herein a method for forming one or more intramolecular disulfide bonds.

A method and apparatus for the manufacture of disulfide bonded peptides is provided, wherein a solution of an oxidizing agent and a solution of a peptide comprising at least two sulfhydryl groups are added simultaneously into a reaction vessel under such conditions that the average concentration of the oxidizing agent inside the reaction vessel is essentially zero during simultaneous addition.