What are the differences between Bradford and BCA assays?

Question

Accepted Answer

Basis of differentiation

Bradford assay

BCA assay

Definition

Is a spectroscopic method technique for measuring the concentration of protein in a solution

Is a lab technique used to measure the total amount of protein in a sample

Accuracy

More accurate

Less accurate

Time

Is relatively fast

Is comparatively more time-consuming

Sensitivity

Is typically more sensitive, capable of detecting protein concentrations as low as 1-20 µg/mL

Is slightly less sensitive, typically detecting protein concentrations in the range of 25-2000 µg/mL

Mechanism

Based on the absorbance shift of Coomassie Brilliant Blue G-250. In its unbound form, this dye is reddish-brown. When the dye binds to proteins, it undergoes a color change from reddish-brown to blue.

Relies on the reduction of cupric ions (Cu²⁺) to cuprous ions (Cu⁺) in the first reaction. In the second reaction, BCA reacts with the reduced cuprous ions (Cu⁺). This reaction forms a stable, deep purple complex.

Compatibility with agents

Is less tolerant of detergents and other chemical additives, with high levels of detergents, reducing agents and buffers, potentially impacting the results

Is more resistant to a broad range of detergents, reducing agents and buffers because of its two-step reaction process

Basis of differentiation	Bradford assay	BCA assay
Definition	Is a spectroscopic method technique for measuring the concentration of protein in a solution	Is a lab technique used to measure the total amount of protein in a sample
Accuracy	More accurate	Less accurate
Time	Is relatively fast	Is comparatively more time-consuming
Sensitivity	Is typically more sensitive, capable of detecting protein concentrations as low as 1-20 µg/mL	Is slightly less sensitive, typically detecting protein concentrations in the range of 25-2000 µg/mL
Mechanism	Based on the absorbance shift of Coomassie Brilliant Blue G-250. In its unbound form, this dye is reddish-brown. When the dye binds to proteins, it undergoes a color change from reddish-brown to blue.	Relies on the reduction of cupric ions (Cu²⁺) to cuprous ions (Cu⁺) in the first reaction. In the second reaction, BCA reacts with the reduced cuprous ions (Cu⁺). This reaction forms a stable, deep purple complex.
Compatibility with agents	Is less tolerant of detergents and other chemical additives, with high levels of detergents, reducing agents and buffers, potentially impacting the results	Is more resistant to a broad range of detergents, reducing agents and buffers because of its two-step reaction process

What are the differences between Bradford and BCA assays?

Posted September 30, 2024