Heme-independent soluble and membrane-associated peroxidase activity of a Zea mays annexin preparation.
Annexins are cytosolic proteins capable of reversible, Ca(2+)-dependent membrane binding or insertion. Animal annexins form and regulate Ca(2+)-permeable ion channels and may therefore participate in signaling. Zea mays (maize) annexins (ZmANN33 and ZmANN35) have recently been shown to form a Ca(2+)-permeable conductance in planar lipid bilayers and also exhibit in vitro peroxidase activity. Peroxidases form a superfamily of intra- or extracellular heme-containing enzymes that use H(2)O(2) as the electron acceptor in a number of oxidative reactions. Maize annexin peroxidase activity appears independent of heme and persists after membrane association, the latter suggesting a role in reactive oxygen species signaling.
Mortimer
Jennifer C
JC
Department of Plant Sciences, University of Cambridge, Cambridge, UK.
Coxon
Katy M
KM
Laohavisit
Anuphon
A
Davies
Julia M
JM