Pectate Hydrolases of Parsley (Petroselinum crispum) Roots

Abstract

The presence of various enzyme forms with terminal action pattern on pectate was evaluated in a protein mixture obtained from parsley roots. Enzymes found in the soluble fraction of roots (juice) were purified to homogeneity according to SDS-PAGE, partially separated by preparative isoelectric focusing and characterized. Three forms with pH optima 3.6, 4.2 and 4.6 clearly preferred substrates with a lower degree of polymerization (oligogalacturonates) while the form with pH optimum 5.2 was a typical exopolygalacturonase [EC 3. 2.1.67] with relatively fast cleavage of polymeric substrate. The forms with pH optima 3.6, 4.2 and 5.2 were released from the pulp, too. The form from the pulp with pH optimum 4.6 preferred higher oligogalacturonates and was not described in plants previously. The production of individual forms in roots was compared with that produced by root cells cultivated on solid medium and in liquid one.

Oligogalacturonate hydrolase with unique substrate preference from the pulp of parsley roots

“…One form of typical exoPG and four forms of OGH were found in parsley roots (Flodrová et al 2007). OGHs with pH optimum 3.6 and 4.2 identified both in soluble and solid fractions of roots as well as enzyme with pH optimum 4.6 found only in roots juice showed preference for oligogalacturonates with DP about six (OGHs6).…”

“…Activity assay OGH10 activity was assayed in 0.1 M acetate buffer, pH 4.6 (Flodrová et al 2007) or 4.7 (except the determination of pH optimum in the pH region 4.3-4.9) at 30…”

“…The activity of other pectate hydrolases was assayed in 0.1 M acetate buffer at a pH value corresponding to the pH optimum of the individual form utilizing the corresponding substrate of preference (Flodrová et al 2007). …”

“…Fractions were suspended, dialysed against distilled water, freeze-dried and analyzed for protein content (Bradford 1976) and pectate hydrolase activities. Individual forms of enzyme were identified from their different pH optima and substrate preferences (Flodrová et al 2007). Optima L-90K preparative ultracentrifuge was used for higher speeds and Allegra X-22R for lower ones (both Beckman Coulter, Fullerton, California).…”

“…This name (and/or oligogalacturonase) is commonly used for microbial oligomerases, too (Hasegawa & Nagel 1968;van Rijssel et al 1993). Even more forms of OGH were found in parsley roots (Flodrová et al 2007). Three of them were similar to enzyme from carrot roots with preference for hexagalacturonate (OGH6).…”