title: Cloning and expression of functional full-length human tissue plasminogen activator in Pichia pastoris.
abstract: Human tissue plasminogen activator (t-PA) plays a pivotal role in the treatment of acute myocardial infarction, ischemic stroke, and deep vein thrombosis. It has the benefit of generating no adverse effects such as fibrinogen depletion, systemic hemorrhage, and immunologic reactions. Human t-PA is a serine-protease enzyme containing 527 amino acid residues in five structural domains. The correct folding of t-PA requires the correct pairing of 17 disulfide bridges in the molecule. A gene encoding full-length human t-PA was cloned into pPICZαA expression vector downstream of alcohol oxidase promoter and α-mating signal sequence from Saccharomyces cerevisiae and flush with the kex2 cleavage site to express the protein with a native N terminus. The methylotrophic yeast, Pichia pastoris GS115 strain, was transformed with this cassette, and methanol utilizing (mut+) transformants were selected for production and secretion of human t-PA into culture media. SDS-PAGE and Western blot analysis showed the expressed bands of t-PA protein. Zymography test indicated suitable folding and proper function of the expressed recombinant human t-PA in conversion of plasminogen to plasmin and gelatin lysis. Amidolytic activity test showed the amidolytic activity of 1,650 IU/ml. The results of this study concluded that P. pastoris methylotrophic yeast can be a suitable alternative for mammalian and prokaryotic expression systems to produce t-PA.
authors.affiliation: Biotechnology Department, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Keivan
authors.initials: K
authors.lastname: Majidzadeh-A
authors.forename: Vahid
authors.initials: V
authors.lastname: Khalaj
authors.forename: Davami
authors.initials: D
authors.lastname: Fatemeh
authors.forename: Hemayatkar
authors.initials: H
authors.lastname: Mahdi
authors.forename: Barkhordari
authors.initials: B
authors.lastname: Farzaneh
authors.forename: Adeli
authors.initials: A
authors.lastname: Ahmad
authors.forename: Fereidoun
authors.initials: F
authors.lastname: Mahboudi
mesh_terms: D003001:Cloning, Molecular; D015870:Gene Expression; D006801:Humans; D010843:Pichia / Q000235:genetics* / Q000378:metabolism; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator