Tomato Fruit Polygalacturonase Isozyme 1 (Characterization of the [beta] Subunit and Its State of Assembly in Vivo)

摘要: Polygalacturonase isozyme 1 (PG1) is a heterodimer comprising catalytic and noncatalytic or [beta] subunit, whereas polygalacturonase 2 (PG2) comprises only the subunit. To assess state of assembly PG1 in vivo, both subunits were purified to homogeneity used study heterodimer. could be reconstituted vitro from subunit PG2 under wide range salt pH conditions, was indistinguishable isolated tomato (Lycopersicon esculentum) fruit. Specific antibodies indicated that present fruit all developmental stages, but absent vegetative tissue. The vivo tested based on differential thermal stability by heating segments ripe pericarp Temperatures well below those required inactivate caused loss activity PG2, suggesting heat-labile vivo. In addition, when extracts rigorously maintained analyzed at 4[deg]C, barely detectable. These results are consistent with hypothesis can assemble spontaneously essentially intact forms artifactually during extraction tissue low temperatures not maintained.