Hemocyanin-derived phenoloxidase reaction products display anti-infective properties

Tarantula hemocyanin shows phenoloxidase activity.

An enzyme generally catalyzes one well defined reaction with high specificity and efficiency. We report here in contrast that the copper protein hemocyanin of the tarantula Eurypelma californicum exhibits two different functions. These occur at the same active site. While hemocyanin usually is an oxygen carrier, its function can be transformed totally to monophenoloxidase and o-diphenoloxidase ...

Hemocyanin-derived Phenoloxidase; Biochemical and Cellular Investigations of Innate Immunity By

SDS-induced phenoloxidase activity of Helix aspersa maxima hemocyanin

Oxygen-transporting protein of the hemolimph of snails Helix aspersa maxima (HaH) was converted from being an oxygen carrier to a form which exhibited phenoloxidase activity by incubation with sodium dodecyl sulfate (SDS). On treatment with 1.73 mM SDS, for 3 min, significant increase of catalytic efficiency of hemocyanin towards substrate catechol (kcat/Km = 34.56 mM.min -1 versus kcat/Km = 0....

Phenoloxidase activity of hemocyanin in whiteleg shrimp Penaeus vannamei: conversion, characterization of catalytic properties, and role in postmortem melanosis.

Latent phenoloxidase activity of hemocyanin (Hc) in whiteleg shrimp Penaeus vannamei was assayed to determine its potential involvement in postmortem melanosis. Conversion of pure 12-mer, but not 6-mer, hemocyanin to phenoloxidase by endogenous (serine proteinases) and exogenous (SDS) effectors demonstrated the need of complex aggregation for displaying enzyme activity. Because Hc was converted...

Anti-infective and cytotoxic properties of Bupleurum marginatum

BACKGROUND Bupleurum marginatum Wall. ex DC (Apiaceae) is a perennial herb widely used in traditional Chinese and Kampo medicine for the treatment of various infectious diseases. The biological activities of B. marginatum have not been fully investigated. This study aims to investigate the antitrypanosomal, antimicrobial and antiviral activities of methanol (ME) and dichloromethane (DCM) extrac...