Lupin peroxidases. I. Isolation and characterization of cell wall‐bound isoperoxidase activity

Abstract

Cell wall fragments, isolated from dark‐grown Lupinus albus L. (cv. multolupa) hypocotyls, and purified by washing with Triton X‐100, did not show detectable contamination by enzyme markers of cytosol or endoplasmic reticulum in which peroxidase activity was also located by electron microscopy. Peroxidase (EC 1.11.1.7) isoenzymes, solubilized from these cell wall fractions by high saline forces, showed a high affinity towards guaiacyl type substrates, whereas syringyl type substrates were not oxidized. On the other hand, both the isoenzyme patterns and the substrate specificity of these cell wall isoperoxidases could be altered by chromatographic and denaturating/renaturating procedures, which break the protein‐phenol interactions, and this suggests the presence of phenol‐induced conformers. These results draw attention to the origin of the enzymatic polymorphism, and catalytic properties, of the peroxidase activity located in the cell wall.

Differential effects of nitric oxide on peroxidase and H2O2 production by the xylem of Zinnia elegans

“…Later, the sections were quickly dried and subsequently centrifuged in a 25 ml syringe barrel placed within a centrifuge tube at 900 g for 5 min at 4°C. Contamination by cytoplasmic constituents, monitored by the activity of glucose-6-phosphate dehydrogenase (Ros Barceló, Muñoz & Sabater 1987), was always less than 1% relative to that found in the cytosolic fraction. To measure peroxidase, IWFs were dialysed overnight against deionized water at 4°C, and subsequently concentrated 10-fold using Centricon 10™ (Amicon Inc., Beverly, Massachusetts, USA).…”

The effects of cold-hardening and Microdochium nivale infection on oxidative stress and antioxidative protection of the two contrasting genotypes of winter triticale

“…POX bands were visualized using the activity staining method described by Ros Barceló [41]. All gels were incubated in staining buffer (50 mM acetatephosphate buffer pH 5, 2 mM 3,3′-diaminobenzidine DAB) for 20 min at RT.…”

Phytochrome induces changes in the immunodetectable level of a wall peroxidase that precede growth changes in maize seedlings

“…3, the R and far-red light (FR) sources (source A) used were those described by Chen and Roux (11). Fluence rates of R were [8][9][10][11][12] jtmol/m2 sec; fluence rates for FR were 15-20 ,4mol/m2 sec.For the data in Fig. 3, R-irradiations were given in a 2-min pulse at 10-20 gmol/m2sec and measured by a quantum sensor (LI-185B; Li-cor, Lincoln, NE) by using a Schott KL1500 fiberoptic microscope illuminator (source B) filtered with a Schott RG610 filter.…”