A Comparison of the Polygalacturonases Produced in vivo and in vitro by Penicillium expansum Thom.

Abstract

SUMMARYPolygalacturonase (PG) was produced by Penicillium expartsum in rotted apples and in liquid culture medium containing pectin; acetone precipitates of the enzyme were prepared from both sources. The PG extracted from apples (in vivo PG) behaved as an endo-PG and degraded sodium polypectate to tetragalacturonic acid. PG from culture filtrates (in vitro PG) before purification had quite different properties, the final hydrolysis product being monogalacturonic acid. PG from both sources was purified by ion-exchange chromatography. The properties of some purified PG preparations were quite different from those of the crude material. None of the purzed in vitro PG released monogalacturonic acid from sodium polypectate, whilst some preparations from both sources had identical endo-PG properties after purification. Changes in the properties of endo-PG produced in vivo and in vitro were apparent during purification and a series of distinct endo-PG's were obtained which yielded unresolved oligomers, tri-or tetragalacturonic acid as h a l hydrolysis products. It is suggested that the changes in behaviour of the various PG preparations during purification were brought about by changes in the molecular configuration of the enzyme, and that such changes could account for some of the variability between enzymes produced in vivo and in vitro.

Extracellular Enzymes of Penicillium

“…He suggested the possibility that mucate is the only true stimulatory compound and that L-galactonate and n-galacturonate undergo oxidative dissimilation by the mold via mucate. Penicillium expansum causes blue mold rot of apples, and a comparison is available between the production of polygalacturonases (Swinburne and Corden, 1969) and pectin lyase (Spalding and Abdul-Baki, 1973) in both apple tissue and artificial media. Formation of both enzymes is repressed by a variety of sugars and also by galacturonate and glutamate, which could explain why their production in artificial culture is greatly increased using dialyzed rather than nondialyzed apple medium .…”

“…(1982) Reese andMandels (1959) Reese et at. (1962( ) Phatf(1947 Olutiola and Akintunde (1979) Awasthi and Mishra (1982) Bush and Codner (1970), Lobanok et al (1977) Spalding and Abdul-Baki (1973), , Swinburne and Corden (1969) Bush and Codner (1970) Olutiola (1983 Durand et at. (1984) Durand et al (1984) Reese et at.…”

The Partial Purification and Properties of Endopolygalacturonase and -L-Arabinofuranosidase secreted by Sclerotinia fructigena

“…That such components may represent polymeric forms was indicated by the present results of the molecular weight estimation with a dialysed concentrated culture filtrate, which gave peaks corresponding to molecular weights of 38,500 and 77,000. It may be significant that Swinburne & Corden (1969) observed changes in the properties of a PG secreted by Peniciilium expansum during purification by ion-exchange chromatography which they attributed to changes in the molecular configuration of the enzyme. Two forms of the Sclerotinia fructigena enzyme in the tannic acid preparation were also detected on strip electrophoresis; these were not further characterized, but both carried a strong overall basic charge at pH 7.6 and pH 8.5.…”

Production of pectolytic and macerating enzyme by Phoma strasseri

“…Swinburne and Corden (17,18) reported changes in the prcperties of a polygalacturonase preparation during purification of the crude enzyme. They suggested that these changes were brought about by an alteration in the molecular configuration of the enzyme, that probably accounted for some of the differences between the enzyme isolated from culture filtrates and diseased plants.…”