Isoperoxidases of (IAA oxidase) oxidase in oat coleoptiles

Abstract

Eight constitutive isoperoxidases were separated by the disc method of polyacrylamide gel electrophoresis from a lyophilized extract of 8-day-old oat (Avena sativa L., cv. Victory) coleoptiles. Both anodic and cathodic isoperoxidases were studied and differences in electrophoretic mobilities and hydrogen donor substrate specificities were revealed. In addition, by enzyme assay, cathodic and anodic isoenzymes were shown to possess differences in peroxidase and IAA (indole-3-acetic acid) oxidase activities.Treatment of coleoptiles with 0.07 mM IAA for 24 h resulted in the repression of two slow-migrating anodic isoperoxidases; however, the same treatment also resulted in the induction of two slow-migrating cathodic isoenzymes which were shown to exhibit peroxidase and IAA oxidase activities.

Indole-3-Acetic Acid Control on Acidic Oat Cell Wall Peroxidases

“…The reduction in peroxidase activity by exogenously applied IAA has been reported in several plant systems (Gordon and Henderson 1973, Morrow and Jones 1986, Ockerse et al 1965, Ockerse and Mumford 1973, Ros Barceló et al 1989), but only a few reports describe the effect of this auxin on peroxidases from the cell walls (Morrow andJones 1986, Ros Barceló et al 1989). In pea internode sections, intercellular peroxidase activity was decreased by IAA treatment, an effect that correlated inversely with the elongation rate (Morrow and Jones 1986), and application of IAA or 2,4 dichlorophenoxiacetic acid to exponentially growing lupin hypocotyls promoted a reduction in the level of free intercellular peroxidases (Ros Barceló et al 1989).…”

“…Catabolism of IAA through oxidation has been demonstrated to be catalyzed by peroxidases in active growing tissues (Gordon and Henderson 1973, Ockerse and Mumford 1973). Several studies indicated that IAA decreased peroxidase activity in plant tissues in which this auxin induces cell elongation (Morrow and Jones 1986, Ockerse and Mumford 1973, Ros Barceló et al 1989).…”

“…Several studies indicated that IAA decreased peroxidase activity in plant tissues in which this auxin induces cell elongation (Morrow and Jones 1986, Ockerse and Mumford 1973, Ros Barceló et al 1989). The inhibited peroxidases include the IAA oxidase activity shown by certain peroxidase isoforms (Gordon andHenderson 1973, Ockerse andMumford 1973). However, in these reports it is not possible to correlate reduced peroxidase activity by IAA with cell enlargement because most of the studies deal with total peroxidase activity present in crude extracts (Gordon and Henderson 1973, Morrow and Jones 1986, Ockerse and Mumford 1973; rarely has it been demonstrated that the measured peroxidase activity came from the cell walls without intracellular contamination (Morrow and Jones 1986, Ros Barceló et al 1989).…”

“…The inhibited peroxidases include the IAA oxidase activity shown by certain peroxidase isoforms (Gordon andHenderson 1973, Ockerse andMumford 1973). However, in these reports it is not possible to correlate reduced peroxidase activity by IAA with cell enlargement because most of the studies deal with total peroxidase activity present in crude extracts (Gordon and Henderson 1973, Morrow and Jones 1986, Ockerse and Mumford 1973; rarely has it been demonstrated that the measured peroxidase activity came from the cell walls without intracellular contamination (Morrow and Jones 1986, Ros Barceló et al 1989). Peroxidases associated with the cell wall compartment are expected to participate in growth modulation because cell walls must be altered for cell enlargement to occur.…”

The effect of plant growth regulators and chlorsulfuron on electrophoretic profiles of soluble proteins, polypeptides and antioxidant enzymes in maize seedlings

“…Significant differences in the manner and degree of influence on the activity of basic peroxidases between growth regulators tested and CHF were observed. It is well known that these enzymes function as IAA-oxidases as well (Gordon and Henderson 1973) and participated in the cessation of plant growth. Recently Quiroga et al (2001) have shown that basic peroxidases function in the lignification too.…”