Disulfide bond modification
| 【Numbering】BK2021071402 | 【CAS】CAS | ||
| 【Item No.】 | 【specification】 | ||
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Disulfide bonds are an indispensable part of the three-dimensional structure of many proteins. We can find these covalent bonds in almost all extracellular peptides and protein molecules.
When the sulfur atom of one cysteine forms a covalent single bond with the sulfur atom of another cysteine at a different position in the protein, a disulfide bond is formed. These ones
Bonds help stabilize proteins, especially those secreted from cells.
The effective formation of a disulfide bond involves many aspects, including proper management of cysteine, protection of the amino acid residues, methods of removing protective groups, and pairing
Methods, etc.
Beike Nano has mature disulfide bond formation technology. If the peptide contains only one pair of Cys, the formation of disulfide bond is simple. Peptides are synthesized by solid phase or liquid phase,
Then it is oxidized in a pH 8-9 solution.
When two or more pairs of disulfide bonds need to be formed, the synthesis process is relatively complicated. Although the formation of disulfide bonds is usually completed at a later stage of the synthesis scheme,
But sometimes the introduction of pre-formed disulfides is conducive to joining or extending the peptide chain. The protecting groups of Cys, which are widely used by Synbiotics, are Bzl, Meb, Mob,
tBu, Trt, Tmob, TMTr, Acm, Npys, etc. We are good at disulfide bond peptide synthesis including:
1. The formation of two pairs of disulfide bonds in the molecule and the formation of two pairs of disulfide bonds between the molecules
2. The formation of three pairs of disulfide bonds in the molecule and the formation of three pairs of disulfide bonds between the molecules
3. Insulin-like peptide synthesis, the formation of two pairs of disulfide bonds between different peptide sequences
4. Synthesis of three pairs of disulfide bond peptides
Why is Cys so special?
※ The side chain of Cys has a very active reactive sulfhydryl group. The hydrogen atom in this group can be easily replaced by free radicals and other groups, so it is easy to be separated from other groups.
The child forms a covalent bond.
※ Disulfide bonds are an important part of the three-dimensional structure of many proteins. Disulfide bridges can reduce the elasticity of the peptide, increase stiffness, and reduce the number of potential conformations. This
Such conformational restrictions are critical to biological activity and structural stability. Its replacement may be dramatic for the overall structure of the protein.
※ Hydrophobic amino acids such as Leu, Ile, and Val are the stabilizers of the helix. Because even cysteine does not form a disulfide bond, it can stabilize the alpha helix. I.e. if all
Cysteine residues are in a reduced state (-SH, carrying free sulfhydryl groups), and a high percentage of helical fragments will be possible.
※ The disulfide bond formed by cysteine is long-lasting for the stability of the tertiary structure. In most cases, S-S bridges between bonds are necessary to form a quaternary structure. Have
The cysteine residues that form disulfide bonds are far apart in the first-order structure.
※ The topology of disulfide bonds is the basis for analyzing the homology of the first-order structure of proteins. Cysteine residues located in homologous proteins are very conserved. Only tryptophan in statistics
It is more conservative than cysteine.
※ Cysteine is located in the center of the catalytic site of sulfhydryl enzyme. Cysteine can directly form an acyl intermediate with the substrate. The reduced form is maintained as a "sulfhydryl buffer"
The cysteine in the protein is in a reduced state. At low pH values, the equilibrium is biased towards the reduced state, -SH form, while in an alkaline environment, -SH is more likely to be oxidized.
Form -SR, and R is anything except hydrogen atoms.
※ Cysteine can also be used to detoxify and react with hydrogen peroxide and organic peroxides.
Message
When the sulfur atom of one cysteine forms a covalent single bond with the sulfur atom of another cysteine at a different position in the protein, a disulfide bond is formed. These ones
Bonds help stabilize proteins, especially those secreted from cells.
The effective formation of a disulfide bond involves many aspects, including proper management of cysteine, protection of the amino acid residues, methods of removing protective groups, and pairing
Methods, etc.
Beike Nano has mature disulfide bond formation technology. If the peptide contains only one pair of Cys, the formation of disulfide bond is simple. Peptides are synthesized by solid phase or liquid phase,
Then it is oxidized in a pH 8-9 solution.
When two or more pairs of disulfide bonds need to be formed, the synthesis process is relatively complicated. Although the formation of disulfide bonds is usually completed at a later stage of the synthesis scheme,
But sometimes the introduction of pre-formed disulfides is conducive to joining or extending the peptide chain. The protecting groups of Cys, which are widely used by Synbiotics, are Bzl, Meb, Mob,
tBu, Trt, Tmob, TMTr, Acm, Npys, etc. We are good at disulfide bond peptide synthesis including:
1. The formation of two pairs of disulfide bonds in the molecule and the formation of two pairs of disulfide bonds between the molecules
2. The formation of three pairs of disulfide bonds in the molecule and the formation of three pairs of disulfide bonds between the molecules
3. Insulin-like peptide synthesis, the formation of two pairs of disulfide bonds between different peptide sequences
4. Synthesis of three pairs of disulfide bond peptides
Why is Cys so special?
※ The side chain of Cys has a very active reactive sulfhydryl group. The hydrogen atom in this group can be easily replaced by free radicals and other groups, so it is easy to be separated from other groups.
The child forms a covalent bond.
※ Disulfide bonds are an important part of the three-dimensional structure of many proteins. Disulfide bridges can reduce the elasticity of the peptide, increase stiffness, and reduce the number of potential conformations. This
Such conformational restrictions are critical to biological activity and structural stability. Its replacement may be dramatic for the overall structure of the protein.
※ Hydrophobic amino acids such as Leu, Ile, and Val are the stabilizers of the helix. Because even cysteine does not form a disulfide bond, it can stabilize the alpha helix. I.e. if all
Cysteine residues are in a reduced state (-SH, carrying free sulfhydryl groups), and a high percentage of helical fragments will be possible.
※ The disulfide bond formed by cysteine is long-lasting for the stability of the tertiary structure. In most cases, S-S bridges between bonds are necessary to form a quaternary structure. Have
The cysteine residues that form disulfide bonds are far apart in the first-order structure.
※ The topology of disulfide bonds is the basis for analyzing the homology of the first-order structure of proteins. Cysteine residues located in homologous proteins are very conserved. Only tryptophan in statistics
It is more conservative than cysteine.
※ Cysteine is located in the center of the catalytic site of sulfhydryl enzyme. Cysteine can directly form an acyl intermediate with the substrate. The reduced form is maintained as a "sulfhydryl buffer"
The cysteine in the protein is in a reduced state. At low pH values, the equilibrium is biased towards the reduced state, -SH form, while in an alkaline environment, -SH is more likely to be oxidized.
Form -SR, and R is anything except hydrogen atoms.
※ Cysteine can also be used to detoxify and react with hydrogen peroxide and organic peroxides.
| Warm tips: Suzhou Beike nano products are only used for scientific research, not for human body,different batches of products have different specifications and performance |
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| Warm tips: Suzhou Beike nano products are only used for scientific research, not for human body,different batches of products have different specifications and performance.The website pictures are from the Internet. The pictures are for reference only. Please take the real object as the standard. In case of infringement, please contact us to delete them immediately. |
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