Amino acids plant materials

Because animals do not synthesize either the aromatic or branched-chain amino acids, these materials can be applied to kill unwanted vegetation without causing harm to domestic animals or humans. Certain derivatives can often be selectively applied to combat noxious plants without appreciable harm to crops. More promising, however, is the prospect of using biotechnology to incorporate genes for enzymes specifically resistant to one of the herbicides into seeds used for crop production. 

The second experimental problem is that incorporation of a material such as loganin (34), or even an amino acid which seems cleady to be a precursor by some biogenetic hypothesis, does not necessarily prove it is a precursor. The material fed may so completely swamp the normal pathways in the plant that the utiliza tion of what was fed generates an aberrant path which nonetheless produces the same product. 

LPC Product Quality. Table 10 gives approximate analyses of several LPC products. Amino acid analyses of LPC products have been pubhshed including those from alfalfa, wheat leaf, barley, and lupin (101) soybean, sugar beet, and tobacco (102) Pro-Xan LPC products (100,103) and for a variety of other crop plants (104,105). The composition of LPCs varies widely depending on the raw materials and processes used. Amino acid profiles are generally satisfactory except for low sulfur amino acid contents, ie, cystine and methionine. 

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Although the first two possibilities can lead to severe problems in the fermentation of amino acids, these problems can be prevented by using proper plant design maintenance of hygienic conditions throughout the operation reservation of large batches of raw material with uniform qualities. Much more severe (and much more difficult to control) are the last two possibilities which will now be discussed in more detail. 

Pyrazol-1 -ylalanine, an isomer of histidine, was isolated from Citrullus vulgaris (watermelon) seed and its structure was confirmed by comparison with synthetic material 107). It was the major free amino acid in the dormant dry seed but was present in only trace amounts in vegetative tissue. While present in seed extracts of other members of the Cucurbitaceae, it has not been identified as occurring in members of other plant families. 

Some of the potential uses of the fats and oils found in plants have been reviewed and some uses of carbohydrate-based polymers briefly discussed. Plants contain a whole variety of other chemicals including amino acids, terpenes, flavonoids, alkaloids, etc. When the potential for these naturally occurring materials are combined with the secondary products that can be obtained by fermentation or other microbial processes or by traditional chemical transformations, the array of chemicals that can readily be created from renewable resources is huge. In this section a few of the more interesting examples are considered. 

The yellow analogues, the betaxanthins, are composed of betalamic acid with amino acids or amines, respectively, amounting to 26 structures known to occur naturally. " Structures unambiguously assigned by NMR spectroscopy usually carry trivial names derived from the plant material from which they have been first isolated. The substitution patterns of betalyanins and betaxanthins hitherto reported together with their particular plant sources are listed in Table 4.4.1 and 4.4.2, respectively. 

Polar organic compounds such as amino acids normally do not polymerize in water because of dipole-dipole interactions. However, polymerization of amino acids to peptides may occur on clay surfaces. For example, Degens and Metheja51 found kaolinite to serve as a catalyst for the polymerization of amino acids to peptides. In natural systems, Cu2+ is not very likely to exist in significant concentrations. However, Fe3+ may be present in the deep-well environment in sufficient amounts to enhance the adsorption of phenol, benzene, and related aromatics. Wastes from resinmanufacturing facilities, food-processing plants, pharmaceutical plants, and other types of chemical plants occasionally contain resin-like materials that may polymerize to form solids at deep-well-injection pressures and temperatures. 

Proteins, the main constituents of the animals body, are polypeptides, biopolymers consisting of many amino acid molecules (the monomers) combined together (see Chapter 11) collagen, for example, the main component of animal skin, is a complex protein consisting of many molecules of amino acids combined together into polypeptide chains (see Fig. 71). Polysaccharides, the essential constituents of plants, also consist of many monosaccharide molecules combined together. Cellulose, the most abundant biological material on earth, which makes up most of the structural... 

Plants synthesize all the amino acids they require. They do so using as raw material carbohydrates, which they make during photosynthesis, and nitrogen, derived from nitrate ions absorbed from the soil. Animals cannot synthesize all the amino acids required for their regular living, health, and growth. Those they cannot synthesize, known as the essential amino acids, are acquired from plants and/or animals they consume as food. Human beings, for example, acquire nine essential amino acids from their diet. 

Witte, C. P., Noel, L. D., Gielbert, J., Parker, J. E. and Romeis, T. (2004). Rapid one-step protein purification from plant material using the eight-amino acid StrepII epitope. Plant Mol. Biol. 55, 135-47. 

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