fluorescent labeling

Peptide fluorescent labeling is simple to operate due to its lack of radioactivity. Therefore, peptide fluorescence labeling is widely used in biological research. The peptide fluorescence labeling method is related to the structure of the fluorescent reagent. For those with free carboxyl groups, the same method as peptide binding reaction is used, and HBTU/HOBt/DIEA method is also used for ligation. Peptides labeled with FITC at the N-terminus need to undergo cyclization to form fluorescein, usually accompanied by the removal of the last amino acid. However, when there is a spacer such as aminocaproic acid, or when the target peptide is cut off from the resin through a non acidic environment, this situation can avoid being cut off by TFA during the cutting process.

People use fluorescently labeled peptides to detect the activity of target proteins, and apply their developed high-throughput activity screening methods to drug screening and development of disease treatment target proteins (such as various kinases, phosphatases, peptidases, etc.).

Positive peptide biochemistry can provide various fluorescent labeled peptides with mature technology.

Here are some common peptide modified fluorescent substance structures:

FITC labeling

FITC (fluorescein isothiocyanate) has relatively high activity, and our company can label FITC on peptides in two ways: (1) labeling FITC on lysine (Lys) or selectively deprotected ornithine side chain amino groups; (2) Label FITC on the N-terminal amino group of the polypeptide.

When labeling at the N-terminus, it is recommended to introduce an alkyl spacer, such as aminocaproic acid (Ahx), between the last amino group and the thiourea bond formed by the reaction of isothiocyanate with the amino group. Link cleavage requires an acidic environment, and peptides labeled with FITC at the N-terminus undergo cyclization to form fluorescein, usually accompanied by the removal of the last amino acid. However, this situation can be avoided when there is a spacer such as aminocaproic acid, or when the target peptide is cleaved from the resin through a non acidic environment. The steric hindrance is considered the main reason for using Ahx before fluorescent dyes, rather than why FITC cannot be directly coupled to peptides.

Ahx or b-Ala can be used as spacers on FITC labeled peptides.

普通荧光修饰

通过Lys侧链氨基连接的荧光修饰

我司常做的荧光物质的激发光波长和发射光波长。可供参考选择：