Higher plants activity

The major anions in the soil solution are CP, HCCfj SO -, and NOJ. The soil solution concentrations can indicate the sulfur and nitrogen availability for plants in those soils. In humid region soils, the anion sum rarely exceeds 0.01 M in the soil solution in arid regions the concentration can reach 0.1 M. The relative amounts of these anions vary with fertilizer and management practices, mineralogy, microbial and higher-plant activity, saltwater encroachment, irrigation water composition, and atmospheric fallout. 

There is an absolute growth requirement for polyamines in some microorganisms, mammalian cells, and higher plants. Active growth and cell division are correlated with increased rates of macromolecular and polyamine synthesis. Increased polyamine biosynthesis during the Gi phase of the cell cycle, just preceding the onset of DNA synthesis in dividing cells, appears to be a universal phenomenon in animals and plants (Slocum et al., 1984). 

Cobalt is one of twenty-seven known elements essential to humans (28) (see Mineral NUTRIENTS). It is an integral part of the cyanocobalamin [68-19-9] molecule, ie, vitamin B 2> only documented biochemically active cobalt component in humans (29,30) (see Vitamins, VITAMIN Vitamin B 2 is not synthesized by animals or higher plants, rather the primary source is bacterial flora in the digestive system of sheep and cattle (8). Except for humans, nonmminants do not appear to requite cobalt. Humans have between 2 and 5 mg of vitamin B22, and deficiency results in the development of pernicious anemia. The wasting disease in sheep and cattle is known as bush sickness in New Zealand, salt sickness in Florida, pine sickness in Scotland, and coast disease in AustraUa. These are essentially the same symptomatically, and are caused by cobalt deficiency. Symptoms include initial lack of appetite followed by scaliness of skin, lack of coordination, loss of flesh, pale mucous membranes, and retarded growth. The total laboratory synthesis of vitamin B 2 was completed in 65—70 steps over a period of eleven years (31). The complex stmcture was reported by Dorothy Crowfoot-Hodgkin in 1961 (32) for which she was awarded a Nobel prize in 1964. 

There are two distinct groups of aldolases. Type I aldolases, found in higher plants and animals, require no metal cofactor and catalyze aldol addition via Schiff base formation between the lysiae S-amino group of the enzyme and a carbonyl group of the substrate. Class II aldolases are found primarily ia microorganisms and utilize a divalent ziac to activate the electrophilic component of the reaction. The most studied aldolases are fmctose-1,6-diphosphate (FDP) enzymes from rabbit muscle, rabbit muscle adolase (RAMA), and a Zn " -containing aldolase from E. coli. In vivo these enzymes catalyze the reversible reaction of D-glyceraldehyde-3-phosphate [591-57-1] (G-3-P) and dihydroxyacetone phosphate [57-04-5] (DHAP). 

Mammals, fungi, and higher plants produce a family of proteolytic enzymes known as aspartic proteases. These enzymes are active at acidic (or sometimes neutral) pH, and each possesses two aspartic acid residues at the active site. Aspartic proteases carry out a variety of functions (Table 16.3), including digestion pepsin and ehymosin), lysosomal protein degradation eathepsin D and E), and regulation of blood pressure renin is an aspartic protease involved in the production of an otensin, a hormone that stimulates smooth muscle contraction and reduces excretion of salts and fluid). The aspartic proteases display a variety of substrate specificities, but normally they are most active in the cleavage of peptide bonds between two hydrophobic amino acid residues. The preferred substrates of pepsin, for example, contain aromatic residues on both sides of the peptide bond to be cleaved. 

AMP-activated protein kinase, AMPK SNF1 complex (fungi) SNF1-related kinase-1 (higher plants)... 

Bjorkman, O. (1968). Carboxydismutase activity in shade-adapted and sun-adapted species of higher plants. Physiologia Plantarum, 21,1-10. 

Cutinase is a hydrolytic enzyme that degrades cutin, the cuticular polymer of higher plants [4], Unlike the oflier lipolytic enzymes, such lipases and esterases, cutinase does not require interfacial activation for substrate binding and activity. Cutinases have been largely exploited for esterification and transesterification in chemical synthesis [5] and have also been applied in laundry or dishwashing detergent [6]. 

Mouillon, J.M. et al., Folate synthesis in higher-plant mithocondria coupling between the dihydropterin pyrophosphokinase and the dihydropteroate synthase activities, Biochem. J., 363, 313, 2002. 

Many different glycosyltransferase activities involved in higher plant wall biosynthesis have been identified in cell free membrane fractions, but in only a few cases has glycosyltransferase activity been retained in detergent-solubilized preparations, and in even fewer cases have any purified polypeptides been identified as plant cell wall glycosyltransferases (29,33). 

J. C. Tarafdar and N. Claassen, Organic pho.sphorus compounds as a phosphorus source for higher plants through the activity of phosphatases produced by plants roots and microorganisms. Biol. Fertil. Soil.t 5 308 (1988). 

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