▁heter olog ous ▁protein ▁expression , ▁giving ▁higher ▁yields ▁of ▁production . ▁▁ 4 : ▁The ▁technology ▁required ▁for ▁gen etic ▁manip ulation ▁of ▁P . ▁past oris ▁is ▁similar ▁to ▁that ▁of ▁Sac char omy ces ▁c ere vis iae , ▁which ▁is ▁one ▁of ▁the ▁most ▁well - stud ied ▁ye ast ▁model ▁organ isms . ▁As ▁a ▁result , ▁the ▁experiment ▁protocol ▁and ▁materials ▁are ▁easy ▁to ▁build ▁for ▁P . ▁past oris . ▁ ▁Dis adv antage ▁As ▁some ▁prote ins ▁require ▁ch aper on in ▁for ▁proper ▁fol ding , ▁P ich ia ▁is ▁unable ▁to ▁produce ▁a ▁number ▁of ▁prote ins , ▁since ▁P . ▁past oris ▁does ▁not ▁contain ▁the ▁appropriate ▁ch aper ones . ▁The ▁techn ologies ▁of ▁ ▁introdu cing ▁gen es ▁of ▁m amm al ian ▁ch aper on ins ▁into ▁the ▁ye ast ▁gen ome ▁and ▁over express ing ▁existing ▁ch aper on ins ▁still ▁require ▁improvement ▁ ▁Com parison ▁with ▁other ▁expression ▁systems ▁In ▁standard ▁mole cular ▁bi ology ▁research , ▁the ▁b acter ium ▁E scher ich ia ▁col i ▁is ▁the ▁most ▁frequently ▁used ▁organ ism ▁for ▁expression ▁system , ▁to ▁produce ▁heter olog ous ▁prote ins , ▁due ▁to ▁its ▁features ▁of ▁fast ▁growth ▁rate , ▁high ▁protein ▁production ▁rate , ▁as ▁well ▁as ▁und em and ing ▁growth ▁conditions . ▁Prote in ▁production ▁in ▁E . ▁col i ▁is ▁usually ▁faster ▁than ▁that ▁in ▁P . ▁past oris , ▁with ▁reasons : ▁Compet ent ▁E . ▁col