What does b-mercaptoethanol do to secretory proteins?also...If you forgot to add b-mercaptoethanol to a secretory protein, would the protein's migration likely speed up or slow down? Why?

β-mercaptoethanol (BME) is a reducing agent commonly used in protein research to break disulfide bonds. Disulfide bonds are strong covalent bonds that form between two cysteine residues, and they are important for protein structure and stability. Secretory proteins, also known as exported proteins, undergo a complex process of folding and modification before they are transported out of the cell.

When BME is added to a protein sample, it reduces the disulfide bonds, causing them to break. By breaking the disulfide bonds, BME unfolds the protein and disrupts its structure. This can be beneficial in several ways:

1. Denaturation: BME can denature proteins, which makes them more accessible for analysis. Denaturation typically occurs by disrupting the secondary and tertiary structure of proteins, which unfold the protein and expose hydrophobic regions.

2. SDS-PAGE: BME is commonly used during Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). SDS-PAGE is a technique used to separate proteins based on size. SDS, a detergent, is used to denature proteins and give them a negative charge. BME is added to reduce disulfide bonds, which facilitates separation of the protein monomers.

Regarding the second part of your question, if you forget to add BME to a secretory protein, the protein's migration during SDS-PAGE is likely to slow down. This is because the disulfide bonds will remain intact, leading to a more compact and folded protein structure. Without disulfide bond reduction, the protein will have reduced mobility due to the increased resistance it faces during gel electrophoresis.