Related Experiment Videos
Dye-binding protein assay using a long-wave-absorbing cyanine probe
Hong Zheng1, Yu Xia Mao, Dong Hui Li
1Department of Chemistry, Xiamen University, Xiamen, 361005, China. hzheng@yanan.xmu.edu.cn
Analytical Biochemistry
|June 5, 2003
Summary
A novel protein assay utilizes a water-soluble cyanine dye that binds to proteins, causing a spectral shift. This reproducible and sensitive method accurately quantifies proteins like human serum albumin (HSA) down to 100 ng/mL.
Area of Science:
- Biochemistry
- Analytical Chemistry
Background:
- Accurate protein quantification is crucial in biological research and diagnostics.
- Existing protein assays may have limitations in sensitivity, speed, or interference.
Purpose of the Study:
- To develop a simple, fast, and reproducible protein assay.
- To characterize the performance of a new cyanine dye-based protein assay.
Main Methods:
- A water-soluble sulfonate heptamethylene cyanine dye was used for protein binding.
- The assay monitors the spectral shift of the dye's absorption maximum from 778 nm to 904 nm.
- Spectrophotometry in the near-infrared range was employed for absorbance measurements.
Main Results:
- The assay demonstrated good reproducibility and color stability for at least 80 minutes.
- Sensitivity reached 100 ng/mL for human serum albumin (HSA).
- Linear ranges varied for different proteins: bovine serum albumin (BSA) 200-2000 ng/mL, HSA 100-2400 ng/mL, and gamma-IgG 200-3000 ng/mL.
Conclusions:
- The developed cyanine dye assay is a sensitive and reproducible method for protein quantification.
- The assay shows minimal interference from common ionic surfactants.
- This method offers a viable alternative for protein analysis in various biological samples.