Isolation and Characterization of Polyphenol Oxidase Isozymes of Clingstone Peach

Abstract

The polyphenol oxidase system in clingstone peach (Prunus persica)

Some kinetic properties of polyphenol oxidase obtained from dill (Anethum graveolens)

“…The reaction was carried out at various temperatures and pH values with the substrates mentioned below. PPO activity was calculated from the linear part of the curve giving absorbance values at 420 nm versus time [37,38,39,40]. One unit of PPO activity (EU/mL.min) was defined as the amount of enzyme that caused an increase in absorbance of 0.001/min [41,42].…”

Diphenol Oxidases, Enzyme-catalysed Browning and Plant Disease Resistance

“…These cite differences in molecular weight, number of subunits, kinetic and electrophoretic properties and pH optima of catecholases from different sources. In addition the maturity of the source and plant organ or organelle, or artefacts formed during purification, may alter the results observed (Galeazzi et al, 1981;Gutteridge and Robb, 1975;Halim and Montgomery, 1978;Hasegawa and Maier, 1980;Janovitz-Klapp etal., 1989;Kellyet al, 1990;Lam and Ho, 1990;Leoni and Palmierri, 1990;Matheis and Belitz, 1977;Murao et al, 1993;Murata etal., 1992;Nakamura etal., 1983;Palmer, 1963;Park and Luh, 1985;Racusen, 1969;Sato, 1982;Walker, 1964aWalker, , 1964bWong et al, 1971;Yurkow and Laskin, 1989;Zawistowski etal., 1988a,b;Zhou et al, 1993). It is still not clear how reliably information obtained from one source of catecholase can be extrapolated to another.…”

Fungal pretreatment of sweet sorghum bagasse with supplements: improvement in lignin degradation, selectivity and enzymatic saccharification

“…One unit of MnP activity was defined as 1 lmol of the phenol red oxidized per minute. Polyphenol oxidase (PPO) was assayed by oxidation of catechol to quinone at 30°C (Wong et al 1971). The reaction mixture of 600 lL contained 100 lL crude enzyme with 500 lL 1.67 mM catechol in sodium phosphate buffer (pH 7.0, 50 mM) (e 400 = 3450 M -1 cm…”