| Journal: | Revista brasileira de fisiologia vegetal |
| Database: | PERIÓDICA |
| System number: | 000279379 |
| ISSN: | 0103-3131 |
| Authors: | Huber, Donald J1 Karakurt, Yasar Jeong, Jiwon |
| Institutions: | 1University of Florida, Horticultural Sciences Department, Gainesville, Florida. Estados Unidos de América |
| Year: | 2001 |
| Volumen: | 13 |
| Number: | 2 |
| Pages: | 224-241 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental |
| English abstract | Pectin depolymerization during fruit ripening has been shown to be largely due to pectinolytic enzymes, including polygalacturonases (E.C. 3.2.1.15) and pectinmethylesterases (E.C. 3.2.1.11). Studies have shown that these enzymes are not the primary determinants of softening, although participation in texture changes during the late stages of ripening seems evident. Pectin depolymerization differs significantly between various fruit types, notably avocado and tomato, even though levels of extractable PG activity in these fruits are similar. Collective evidence indicates that the activities of some cell wall enzymes are restricted in vivo, with maximum hydrolytic potential expressed only in response to tissue disruption or wounding. In contrast, other enzymes reported to participate in pectin degradation, notably beta-galactosidases/exo-galactanases, exhibit in vitro activity far below that anticipated to be required for the loss of cell wall galactosyl residues during ripening. Factors controlling in vivo hydrolysis have not been fully explored but might include apoplastic pH, cell wall inorganic ion levels, non-enzymic proteins including the noncatalytic beta-subunit and expansins, wall porosity, and steric hindrances. Recent studies of cell wall metabolism during ripening have demonstrated an orderly process involving, in the early stages, cell wall relaxation and hemicellulose degradation followed, in the later stages, by pectin depolymerization. A limited number of studies have indicated that radical oxygen species generated ei |
| Disciplines: | Agrociencias, Biología, Química |
| Keyword: | Frutales, Biología celular, Fisiología vegetal, Bioquímica, Pectina, Membranas, Oligogalacturónidos, Poligalacturonasa, Apoplasto, Lípidos |
| Keyword: | Agricultural sciences, Biology, Chemistry, Fruit trees, Cell biology, Plant physiology, Biochemistry, Pectin, Membranes, Oligogalacturonides, Polygalacturonase, Apoplast, Lipids |
| Full text: | Texto completo (Ver HTML) |
