Isolation and characterization of the ALP1 protease from Aspergillus fumigatus and its protein inhibitor from Physarium polycephalum
Davies, D.A.; Kalinina, N.A.; Samokhvalova, L.V.; Malakhova, G.V.; Scott, G.; Volynskaia, A.M.; Nesmeianov, V.A.
Bioorganicheskaia Khimiia 31(3): 259-268
2005
ISSN/ISBN: 0132-3423 PMID: 16004384 Document Number: 587825
It is known that Aspergillus fumigatus secretes a serine protease ALP I of the subtilisin family in the presence of extracellular protein substrates. We found conditions of A. fumigatus culturing that provide a high ALP I activity inside cells without induction by extracellular proteins. The identity of the properties of the secreted and intracellular enzymes was shown. A thermostable protein inhibitor of the ALP I protease was isolated from the plasmodium of the myxomycete Physarum polycephalum. Its molecular mass is 32-33 kDa. The inhibitor inhibits the ALP1 protease activity with IC50 of 0.14 μM. This protein was also shown to be a less efficient inhibitor of the activity of HIV-1 protease (IC50 2.5 μM).