OXIDIZED LOW-DENSITY-LIPOPROTEIN INHIBITS THE HEMOLYTIC-ACTIVITY OF ASP-HERNOLYSIN FROM ASPERGILLUS-FUMIGATUS

We have examined the effect of chemically modified human low density l ipoproteins (LDLs), acetylated LDL and oxidized LDL, on the hemolytic activity of Asp-hemolysin. Oxidized LDL, but not acetylated LDL, inhib ited the hemolytic activity of this toxin. The inhibitory effects of o xidized LDL increased with the time of Cu2+-induced LDL oxidation. Sim ilar inhibition was observed in the filtrate which was separated from the incubation mixture of Asp-hemolysin with oxidized LDL (for 2 h of oxidation) following ultrafiltration through a membrane with a molecul ar mass cutoff of 100 000. However, at longer LDL oxidation times, the inhibition by the filtrates was less than the control mixture without ultrafiltration. We suggest that the inhibition by oxidized LDL was d ue to the binding of oxidized LDL to Asp-hemolysin at shorter LDL oxid ation times (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.