An Apparent Cellulase Complex in Tomato (Lycopersicon esculentum L.) Fruit

Abstract

Four enzyme-containing fractions were separated by ammonium sulfate fractionation of 2-day, postbreaker tomato (Lycopersicon esculentum L cv. Manhattan). The

Cell Wall Degrading Enzymes and the Softening of Senescent Strawberry Fruit

“…3) is consistent with values reported for both plant and microbial enzymes (Stevens, 1955;Hinton and Pressey, 1974). The strawberry enzyme is unlikely to be a true "Cr" cellulase (Sabotka and Stelzig, 1974) as we find that it does not attack insoluble cellulose, and is presumably a "CX -type" cellulase. Both "endo" and "exo" activity of polygalacturonase and polymethylgalacturonase appear to be absent from strawberry fruit.…”

Ultrastructural Changes in the Walls of Ripening Avocados: Transmission, Scanning, and Freeze Fracture Microscopy

“…Additional support for this view was presented by BEN-AIRE, KISLEV, and , who observed a similar pattern of degradation of the middle lamella in firm apple and pear tissue which had been treated with exogenous polygalacturonase and in untreated tissue which had been allowed to ripen naturally. Although the apparent breakdown of the wall fibrils has been correlated with an increase in cellulase activity in many of these tissues (HOBSON 1968;LEWIS and VARNER 1970; SOBOTKA and STELZIG 1974;PESIS et al 1978 tween the ultrastructure of walls treated with cellulase and the changes which occur naturally in tissues with high cellulase activities. In both instances, separation and loss of the fibrillar components of the wall were evident.…”

A Possible Role for Cellulose and Cx-cellulase Activity in Locular Gel Formation in Tomato Fruit

“…Sabotka and Stelzig (14) reported the presence of a cellulase complex in ripening tomato fruit, although they did not demon strate a reduction in tissue cellulose content. Fruit softening involves the enzyme-me diated hydrolysis of pectins.…”

“…Cx-cellulase alone will not degrade crystalline cellulose (12). Other enzymes, including cellobiase (pglucosidase), which has been reported in to mato fruit (11,14), are known to be neces sary for depolymerization of cellulose ( 12). Enzyme extracts prepared from gel tissue were capable of hydrolyzing carboxymethylcellulose to monosaccharide (not shown), pre senting evidence that enzymes other than Cxcellulase participated.…”