Plant cell-walls enzymes bound

Heath I.B. 1974. A unified hypothesis for the role of membrane bound enzyme complexes and microtubules in plant cell wall synthesis. J Theor Biol 48 445 149. 

Ricard J, Noat G, Crasnier M, Job D 1981 Ionic control of immobilized enzymes Kinetics of acid phosphatase bound to plant-cell walls. Biochemistry J 195 357-367... 

Cell-wall-bound enzymes in monocots have been less extensively studied than in dicots. Moreover, the majority of studies with this class of plants has been conducted with oat coleoptiles. 

Many DPO preparations from higher plant sources, such as fruits and leaves, are particulate in nature, because, in these systems, the enzyme appears to be bound to the membranes of the chloroplast grana or to cell wall components. The 02 electrode assay is especially advantageous for such preparations, since their turbidity could interfere with spectrophotometric assays. 

Plant cell vacuole Plant cells usually contain one or more membrane-bounded vacuoles. These are used to store nutrients (e.g. sucrose), water, ions and waste products (especially excess nitrogen-containing compounds). Like lysosomes in animal cells, vacuoles have an acidic pH maintained by H+ pumps in the membrane and contain a variety of degradative enzymes. Entry of water into the vacuole causes it to expand, creating hydrostatic pressure (turgor) inside the cell which is balanced by the mechanical resistance of the cell wall. 

The secondary compounds or enzymes accumulated in the neighborhood of the plasma membrane, e.g., the constituents of the cell wall and the epidermis of plant cells, are either insoluble due to polymerization (cellulose, hemicellulose, lignin, cutin, suberin, sporopoUenin) or are trapped by a sieve effect due to the network of ceU wall constituents. Certain enzymes, however, such as the malate dehydrogenase involved in lignification (D 22.2.3), are also covalently bound to the cell wall. Low molecular compounds are able to penetrate the cell wall and may be washed out into the surroundings. 

Plant synthates, primarily intended for the developing seed, are the main nutrition source to the fungus (Mower and Hancock, 1975) which obviously is exploited at about 5 dpi depending on the ergot species. To use this natural sink, several enzymes are secreted such as the cell-wall bound inducible fructosyltransferase (invertase) (Bassett et ah, 1972 Taber, 1985 Tudzynski et ai, 1995) and the fungal foot is developed structurally for attaching and absorbing (Luttrell, 1980). While intense exudation of honeydew is reported to occur without penetration... 

The vacuole comprising most mature plant cells contains secondary metabolites and enzymes. The cell envelope is composed of cellulosic cell walls bound by pectinaceous middle lamella. A phospholipid-bilayer membrane is located on the inside of the cell wall (plasmalemma), as well as around the vacuole (tonoplast). Disruption of the cell or vacuole membrane leads to the release of hydrolytic enzymes which cause the degradation of pectins or cellulose. This in turn weakens the cell wall and tissue structure and leads to a loss of firmness and crispiness due to a dissipation of the intracellular osmotic pressure (turgor) (Taiz and Zeiger, 2007). 

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