Plants storage proteins

Gliadins are prolamins, a group of plant storage proteins with a high proline content, found in the seeds of cereal grains wheat (gliadin), barley (hordein), rye (secalin), corn (zein) and, as a minor protein, avenin in oats. 

Fukushima, D. (1991b). Structures of plant storage proteins and their funetions. Food Rev. Int. 7(3), 351-381. 

Plant storage proteins are found in high concentrations in seeds, especially in leguminous plants, in which the storage proteins constitute up to 25 percent of the dry weight of the seed. These proteins have no known enzymatic function and often exist within separate vesicles (packets) in the seeds. In addition to their importance to the germinating seed, these plant storage proteins are a valuable source of human nutrition, see also Iron Lipids Nucleic Acids Proteins Toxicity Transport Protein. 

Marcone, M.F. Biochemical and biophysical properties of plant storage proteins a current understanding with emphasis on 1 IS seed globulins. Food Res. Int. 1999, 32, 79-92. 

Probably no other plant protein, or for that matter any other crop, is studied more than soy protein and soybeans. Perhaps this is due to the fact that no other grain contains as much protein—on the order of 40% moisture-free basis (mfb). Soybeans deposit nitrogen and photosynthate as storage proteins to support the germinating plant. Storage proteins are stored in protein bodies and are thus separated from degrading enzymes until germination. 

By analogy with animal systems, the function of signal sequences in plant storage proteins is to facilitate the translocation of the storage protein into the lumen of the endoplasmic reticulum (ER) as the first step in intracellular transport. Protein folding and disulfide bond formation are considered to occur within the lumen of the endoplasmic reticulum, and may be assisted by molecular chaperones and by the enzyme protein disulfide isomerase respectively [83]. The precise mechanism of intracellular transport of storage proteins from their site of synthesis to their site of deposition are still largely unknown but a two-way hypothesis has been proposed by Shewry [45]. 

Plant storage proteins are a major agricultural commodity. More than 50 millions of tons of seeds, containing from 20 to 30% of storage proteins, are harvested annually. These seeds usually contain oil in an amount equal to or greater than the content of protein. About 15 millions of tons of the seeds are harvested in the United States, about 10 millions in China, and about 5 millions in India. 

Finally, animal, plant and microbial tissues have been shown to contain the iron storage protein ferritin. The animal protein has been extensively studied, but the mechanism of iron binding has not been completely resolved (29). Animal tissues contain, in addition, a type of granule comprised of iron hydroxide, polysaccharide and protein. The latter, called hemosiderin, may represent a depository of excess iron (30). Interestingly, a protein with properties parallel to those of ferritin has been found in a mold. Here the function of the molecule can be examined with the powerful tools of biochemical genetics (31). 

In monocotyledonous plants, including all the cereals, storage proteins are found mainly in the endosperm. The major storage compounds are carbohydrates rather... 

LOXs are normally present in the seeds of plants, although LOXs do not have a clear physiological role in seed development, because no negative effects on crop performance were observed in LOX-deficient seeds as compared with a normal line. For this reason, the possible function of seed LOXs as storage proteins is considered. 

Limongelli G, Laghetti G, Perrino P, Piergiovanni AR (1996) Variation of seed storage protein in landraces of common bean (Phaseolus vulgaris L.) from Basilicata, Southern Italy. Plant Breed 119 513-516... 

To the best of our knowledge, there is one host which conforms to the structure of an Archimedean dual. Harrison was the first to point out that the quaternary structure of ferritin, a major iron storage protein in animals, bacteria, and plants, corresponds to the structure of a rhombic dodecahedron. [45] This protein, which is approximately 12.5 nm in diameter, consists of 24 identical polypeptide subunits (Fig. 9.18), and holds up to 4500 iron atoms in the form of hydrated ferric oxide with... 

Storage. Plants contain special storage proteins, which are also important for human nutrition (not shown). In animals, muscle proteins constitute a nutrient reserve that can be mobilized in emergencies. 

Ferrihydrite is the iron oxide with the most widespread distribution in living organisms. In the form of ferritin, an iron storage protein, it is found in all organisms from bacteria through to man (in heart, spleen and liver). It occurs in plants as phytoferritin (review by Seckback, 1982). Ferritin plays a key role in iron metabolism it maintains... 

One way is to label the pre-existing vesicles, and then follow the destiny of the label in the vesicle size distribution. The label that has been used to this aim is ferritin, which has been entrapped into vesicles. Ferritin is an iron-storage protein in plants and mammals, and consists of a hollow protein shell of c. 12 nm containing... 

Grierson, C., Du, J.S., de Torres Zabala, M., Beggs, K., Smith, C., Holdsworth, M., and Bevan, M. (1994). Separate cis sequences and trans factors direct metabolic and developmental regulation of a potato tuber storage protein gene. Plant J. 5(6) 815-826. 

Other therapeutic proteins produced in plants include leuenkephalin, a neuropeptide produced in B. napus and Arabidopsis as part of the seed storage protein 2S albumin. The peptide was proteolytically cleaved from the storage protein and recovered by high-performance liquid chromatography (HPLC). In addition, a biologically active form of the human... 

This iron storage protein is widely distributed in many mammalian cells, and also in invertebrates, plants, fungi and a number of bacteria, where it is associated with a fe-type cytochrome. There have been considerable advances recently in the understanding of its structure and physiological function.1093 1098... 

The addition of copper, zinc, cadmium or mercury to animals results in the synthesis of a cysteine-rich protein called metallothionein.1147-1149 These proteins have been isolated from a number of sources, and have molecular weights in the range 6000 to 12 000 with a cysteine content of about 30-35% of the total amino acid content. They have also been found in microorganisms and plants. These proteins are thought to play an important role in the storage of zinc and copper, and as a result of their storage capacity, are able to bind and detoxify cadmium and mercury. 

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