Guanidine HydrochlorideAnd urea-who is the better protein transsexual?
In general, guanidine hydrochloride and urea can be used as denatured agents for proteins. The protein denaturation curves caused by guanidine hydrochloride and urea are often used to estimate the stability of protein conformation (the conformation difference between natural and denatured proteins), so are the results obtained by using these two denatured agents consistent? Here's a glimpse of the results of the study by Monera and others .
Although urea and guanidine hydrochloride are commonly used denatured agents of protein, but they are still different in the basic molecular structure, urea is a neutral molecule, guanidine hydrochloride has ionic properties. Based on the above facts, they speculated that the data of protein degeneration caused by guanidine hydrochloride and urea could be estimated to affect the stability of protein by electrostatic action. To this end, they specially designed 4 curl protein analogues, the electrostatic attraction of the chain and the chain bond in the molecule gradually into the repulsive force. Then, guanidine hydrochloride and urea were used as denatured agents to detect the denaturation curve data of protein.
The results showed that for 4 protein analogues, [the value of guanidine hydrochloride]1/2 was very close to (3.5M), and the difference between the energy values of the stability of four protein analogues measured was close to 0 (0.2 kcal/mol); [The value of urea]1/2 decreases gradually as the attraction within the protein molecule gradually becomes repulsive force, and the difference in the energy value that characterizes the stability of protein analogues is greater than 0. These results show that the ionic properties of guanidine hydrochloride can shield the electrostatic action in the protein, while the neutral molecular urea does not have shielding effect.
From the above-mentioned experiments designed by Monera and others, we have learned that when estimating the stability of protein conformation, we first need to confirm that the effect of electrostatic action on the stability of protein conformation is the size of the protein system studied. If electrostatic action contributes greatly to the stability of protein conformation, the experimental results obtained by using guanidine hydrochloride as a denatured agent will have a large error. Therefore, in the protein denaturation experiment, we need to consider the properties of the subjects and the transsexuals themselves in a comprehensive manner.