Question

a)Gilbert is doing a SDS-PAGE experiment and he cannot find sodium dodecyl sulfate (SDS) for the experiment. He wants to use the household detergent to replace SDS and he said that the cancer cells are easily being lysed even by household detergent. Will he have a successful SDSPAGE result? Discuss how SDS works.

b)Experiments have shown that a defective gene gives a defective enzyme. Hence there is argument of that one gene is responsible for making one enzyme. Discuss whether this statement is correct or not. Give ONE example to support.

Answer 1

a) SDS page experiment is an analytical technique to seperate proteins based on their molecular weight.

When proteins are seperated by electrophoresis through gel matrix, smaller proteins will migrate faster due to less resistance from gel matrix.

In SDS page experiment, use of SDS and polyacrylamide gel eliminates the influence of structure and charge and proteins are seperated based on polypeptide chain length.

SDS is a detergent with strong protein denaturing effect and bind to protein. They cleave disulphide bonds for proper folding and then unfolds to linear chain with negative charge.

detergents are amphiphatic compounds with nonpolar hydrophobic tail and polar hydrophilic head. Detergents are of ionic type and non ionic type.

Non ionic aren't generally used for gel electrophoresis due to their limited ability to break non covalent interaction between proteins aminoacids . Household detergents mostly contains both anionic and non ionic surfactants. So using household detergents to replace SDS will not give desirable result.

b)