Protein Expression


Target genes of interest cloned in appropriate expression vectors are introduced into host cells. To increase the probability that a given protein will be expressed in a soluble and active form, and in high yield, several expression systems are used. These include bacterial systems and three eukaryotic systems - yeast, insect and mammalian cells. Expression is screened on a small scale in 4-10 ml cultures, and soluble and insoluble cellular fractions are analyzed by SDS-PAGE for protein expression. Once optimal conditions have been determined, large-scale cultures (1-5L) are used to obtain greater amounts of protein.