Inactivity of recombinant ELA2B provides a new example of evolutionary elastase silencing in humans.

ABSTRACT: The archetypal mammalian elastase (ELA1) is not expressed in the human pancreas, because evolutionary mutations suppressed transcription of the ELA1 gene.In this study, we tested the theory that the unique duplication of the ELA2 gene in humans might compensate for the loss of ELA1.Recombinant ELA2A and ELA2B were expressed in Escherichia coli, and their activity was tested on Glt-Ala-Ala-Pro-Leu-p-nitroanilide, DQ elastin and bovine milk protein.Surprisingly, recombinant ELA2B was completely devoid of proteolytic activity, while ELA2A readily hydrolyzed all three test substrates. Furthermore, ELA2A formed an SDS-resistant complex with alpha1-antitrypsin, whereas ELA2B did not bind covalently to the inhibitor. Finally, chimeras and point mutations engineered between ELA2A and ELA2B revealed that multiple evolutionary mutations inactivated ELA2B.The results indicate that ELA2B is not an elastase enzyme and confirm that ELA2A is the major elastase in the human pancreas.

SUBMITTER: Szepessy E 

PROVIDER: S-EPMC1447606 | biostudies-literature | 2006

REPOSITORIES: biostudies-literature