Sage-Tips

Can two different proteins have the same molecular weight?

The differences in molecular weight caused by differences in the R groups are not enough to allow a separation. If two proteins migrate the same +SDS they are assumed to be of approximately the same molecular weight because they are about the same length (contain the same # of amino acids).

What do you mean by isoelectric point explain why different acids have different isoelectric points?

Isoelectric and isoionic points The isoelectric point is defined as the pH at which no net migration takes place in an electric field, while the isoionic point is defined as the pH at which there is no net charge on the molecule. Type A or acid-processed gelatins have isoelectric points that can vary from 6.5 to 9.0.

How does the isoelectric point relate to a molecule?

The isoelectric point (pI) is the pH at which a particular molecule carries no net electrical charge. The net charge on the molecule is affected by the pH of its surrounding environment and can become more positive or negative due to the gain or loss of protons, respectively.

What does isoelectric point depend on?

The exact value can vary widely, depending on material factors such as purity and phase as well as physical parameters such as temperature. Moreover, the precise measurement of isoelectric points can be difficult, thus many sources often cite differing values for isoelectric points of these materials.

Why do proteins have different weights?

Proteins undergo post-translational modulation (glycosylation, acetylation, binding with other proteins) as well as protease -dependent degradation, both of which cause several different MW (molecular weight) proteins.

Why at isoelectric point proteins becomes less soluble while above and below that isoelectric point proteins become more soluble?

A protein has its lowest solubility at its isoelectric point. If there is a charge at the protein surface, the protein prefers to interact with water, rather than with other protein molecules. This charge makes it more soluble. Without a net charge, protein-protein interactions and precipitation are more likely.

Why do proteins precipitate at their isoelectric point?

The isoelectric point (pI) is the pH of a solution at which the net charge of a protein becomes zero. However, at the pI, the negative and positive charges are balanced, reducing repulsive electrostatic forces, and the attraction forces predominate, causing aggregation and precipitation.

How does isoelectric point affect proteins?

At the isoelectric point, a protein has no net charge. Above the isoelectric point, a protein carries a net negative charge—below it, a net positive charge. When this pH gradient is in development, protein molecules simultaneously migrate in the solution until these molecules reach their protein isoelectric point.

Why does there two different bands of GFP at different molecular weights Why did this occur which band is which?

It will appear as multiple bands, because each of the bands contains proteins from the mixture that have a specific molecular weight. GFP and BFP both consist of 238 amino acids, but differ in the identities of 2 amino acids.