Storage cells, degradation

The internal storage capacity is limited by the number of storage cells. Excreted alkaloids which are dissolved in the medium are exposed to catalytic activities in the medium (e.g., peroxidases) and can thus be degraded as was demonstrated for quinolizidine alkaloids in lupine cell cultures (92). A role for peroxidases in product degradation has been recently demonstrated for indole alkaloids produced by suspension cultures of Tabemaemontana. Reduction of peroxidase activity by removal of Ca ions from the medium resulted in the formation of the alkaloid... 

Athenstaedt, K Daum, G. The life eycle of neutral lipids synthesis, storage and degradation. Cell Mol Life Sci., 2006, 63, 1355-1369. 

Synthesis, storage, and degradation of secondary products may go on simultaneously in different compartments of one cell. This cannot occur without continuous movement in and out of the storage compartments, e.g., the vacuoles of plants. Intracellular compartmentalization is especially important in the regulation of the amount of this type of secondary compounds. In several instances, however, the synthesis of secondary products and their further transformation/ degradation are part of different programs of cell differentiation. In this case biosynthesis and transformation and/or degradation are separated in space and/ or time. 

Goodpaster BH, Theriault R, Watkins SC, Kelly DE (2000) Intramuscular lipid content is increased in obesity and decreased in weight loss. Metabolism 49(4) 467-472 Athensteadt K, Daum G (2006) The life cycle of neutral lipids synthesis, storage and degradation. Cell Mol Life Sci 63 1355-1369... 

NH3 is another typical contaminant in PEM fuel cell anodes. Trace amounts of NH3 in a fuel cell system will cause significant fuel cell degradation [82-86]. NH3 in the fuel stream originates mainly from hydrogen production and storage, due to several causes ... 

Parathyroid hormone also exists in storage vesicles. As much as 80-90% of the proPTH synthesized is degraded before it enters this final storage compartment, especially when Ca + levels are high in the parathyroid cell (see above). PTH is secreted when Ca is low in the parathyroid cells, which contain a several-hour supply of the hormone. 

After reuptake into the cytosol, some noradrenaline may be taken up into the storage vesicles by the vesicular transporter and stored in the vesicles for subsequent release (see above). However, it is thought that the majority is broken down within the cytosol of the nerve terminal by monoamine oxidase (MAO ECl.4.3.4). A second degradative enzyme, catechol-O-methyl transferase (COMT EC2.1.1.6), is found mostly in nonneuronal tissues, such as smooth muscle, endothelial cells or glia. The metabolic pathway for noradrenaline follows a complex sequence of alternatives because the metabolic product of each of these enzymes can act as a substrate for the other (Fig 8.8). This could enable one of these enzymes to compensate for a deficiency in the other to some extent. 

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