Nitrogenous Extractives

The aim of Chapter 5 is to integrate in a general way the different trends in the literature and indicate where the reader can find specific details concerning the chemistry of nitrogenous extractives such as amino acids, proteins, nucleic acids, and alkaloids, and their products that occur in and beyond the lignocellulosic cell wall. Since most of the literature is covered mainly to 1983, a few key references have been added to bring selected topics up to date. The expectation is that with the further development of useful experimental systems we would be able to explain eventually why and where such compounds occur and how they can be used to our benefit. 

Another major nitrogenous constituent in trees is chlorophyll, but this is essentially absent from woody tissues. The traces of nitrogen-containing compounds in woody tissues often represent intermediary metabolites and translocated forms (Sect. 5.1), and compounds more typical of end-products of metabolism such as the alkaloids (Sect. 5.2). Alkaloids originate from acetate-malonate pathway, the mevalonate pathway, and various amino acid pathways. 

1 Amino Acids, Proteins, Enzymes, and Nucleic Acids 

The natural occurrence and the role of free and bound amino acids, proteins, nucleic acids, and related products (e.g., 8, 42, 116) are described in relation to factors determining the composition of the lignocellulosic cell wall. The biosynthesis of extraneous nitrogenous compounds involves a sequence of events that stem from molecular reactions inside cells, on the surfaces of cells, and in the soluble component of plant cell walls. 

Usually growth and development are integrated by linkages of daughter cells composing tissues and organs that evolve during the life cycle of the woody plant. 

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Leinweber, R, and Schulten, H.-R. (2000). Nonhydrolyzable forms of soil organic nitrogen Extractability and composition. J. Plant Nutr. Soil Sci. 163,433-439. 

Wheat Acylation Increased nitrogen extractability and viscosity. Dissociation into subunits (44)... 

These four purine alkaloids are much more important as animal than as plant constituents. Together with creatine, methyl guanidine acetic acid (p. 441), and creatinine, the anhydride of creatine, they constitute the greater part of what are termed the nitrogenous extractives of muscular tissue. They are present in ordinary beef extract and may be isolated from it. In addition to being present in muscular tissue they are mostly found in the brain, thymus, liver, kidney, spleen and pancreas. Xanthine and hypoxanthine are also present in urine, being the elimination product of caffeine in food. Also associated with... 

S. Severin et ai.. Nitrogenous extractive compounds of muscle tissue of invertebrates. Comp. Biochem. Physiol., 43B (1972) 369-381. 

Scientific name Common name Water Lipids Protein and nitrogenous extractives (total N X 6.25) Protein ... 

Water content Protein content Nitrogenous extractives Glycogen References... 

The quantitative composition of liquid sulfur as determined by HPLC analysis after quenching in liquid nitrogen, extraction with C 2 and separation from the insoluble is shown in Table 3 [93]. These data are the most reliable information about the composition of liquid sulfur in the tempera-... 

Grounding of 20 berry skins to a fine powder with liquid nitrogen Extraction with 3 volumes (v/w) of buffer pH 7.5 (Tris-HCl 0.1 M, ethylenediaminetetraacetic acid (EDTA) 5 mM, phenylmethanesulfonylfluoride ImM, 2-mercaptoethanol 2%, KC1 0.1M, sucrose 0.7M, PVPP 1%) under stirring at 4°C for lh... 

This was observed for our basic nitrogen extracts but not for ii-alkane or neutral fuel samples. We attribute this phenomenon to the presence of water in the basic nitrogen extracts water rapidly loses a hydrogen atom to the radical cation generated by FI. 

Sample preparation Condition a Bond Elut C8 SPE cartridge with 5 mL MeOH and 5 mL water. 20 mL Milk + 1 mL 1 M oxalic acid, heat at 60° for 10 min, centrifuge for 10 min, remove the supernatant and add it to 20 mL water and 400 p-L triWtylamine, shake well, add to the SPE cartridge, wash with two 2.5 mL portions of water, elute with 2.5 mL MeOH. Evaporate the eluate to dryness under a stream of nitrogen, extract the residue with three 100 pL portions of 50 mM pH 6.0 potassium phosphate buffer, filter (0.2 pm), inject an aliquot of the filtrate. (Buffer w-.s 545 mL 100 mM citric add, 455 mL 200 mM Na2HP04, and 74.4 g EDTA, adjust to pH 4.5 with ammonium hydroxide, make up to 2 L with water.)... 

Soluble nitrogen extract from malt at 65 expressed in per cent. 

Nitrogenous Extract of an English Malt at Different Temperatures... 

A question of the greatest importance in the brewery is that of water. If we examine the influence exerted by the composition of the water used in brewing on the quantity of soluble nitrogen extracted at 65°, we find that distilled water dissolves a much larger quantity of soluble nitrogen than a water containing certain mineral salts, like the calcium and the alkali carbonates. The differences, as Fernbach and Hubert have shown, must be attributed to the transformation of the phosphates of the malt from primary (mono-metallic) into secondary (bi-metallic), under the influence of carbonates, a reaction which causes a partial inhibi-... 

At about the same time the calcium cyanamide process was perfected. Calcium carbide, produced by reaction of lime with coke in an electric furnace, was converted to calcium cyanamide (CaCN2) by reaction with pure nitrogen extracted from the air. The product could be used directly as a fertilizer, or it could be hydrolyzed to form ammonia. 

The occurrence of nitrogenous compounds, particularly in cells in mature parts of the tree, may represent physical, chemical, and biological changes over the life cycle. For dead woody cells that compose the vascular system, the nitrogenous extractives may reflect the recent past history of the cells and the enzymes that have survived cellular differentiation. Labile enzymes are present in the secondary walls of differentiated reaction wood. Peroxidase, which is a universally stable enzyme in cell walls, cannot be detected histochemically in walls of dead cells (120). 

Historically, nitrogenous extractives are often described in terms of their natural occurrence, chemistry, and taxonomy. This was true at least until cells and tissues could be brought into the laboratory and controlled under more convenient cultural conditions. Much of the recent scattered literature therefore combines chemical analysis and cell and tissue culture methods with variables associated with experimental systems. For the woody perennials, greater emphasis is now placed on cell wall synthesis, problems of cellular differentiation, soluble compartments in the cell wall, and a wide range of specialized topics (Tables 5.1.1 -5.1.3). 

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