Irreversible Inhibition of Trypsin by the Disulfide Form of Human Alpha-1 Proteinase Inhibitor
The inhibitory properties of the disulfide form of human a-1 proteinase inhibitor (a-1-Pl) were studied, using bovine trypsin as the target protease. Antiprotease activity was found to be kinetically irreversible; treatment of the enzyme-inhibitor complex with a-2 macroglobulin failed to restore the observed esteratic activity of trypsin. a-1-Pl*E was unstable to SDS-PAGE under reducing conditions: A single protein band was observed, with Mr corresponding to 52 000. The results were compared to reports on the reduced (sulfhydryl) form of a-1-Pl, where the enzyme-inhibitor complex is stable both kinetically and electrophoretically. The difference between the two forms of a-1-Pl suggests that the electrophoretic stability of reduced a-1-Pl*E complexes may be due to the presence of an intermolecular disulfide bond between the two proteins.
0RTAPAMUK, 0ya; SÜMER, Nilgün; and ÖZER, İnci (1996) "Irreversible Inhibition of Trypsin by the Disulfide Form of Human Alpha-1 Proteinase Inhibitor," Turkish Journal of Medical Sciences: Vol. 26: No. 2, Article 14. Available at: https://journals.tubitak.gov.tr/medical/vol26/iss2/14