Plants acid phosphatase

In soil, the chances that any enzyme will retain its activity are very slim indeed, because inactivation can occur by denaturation, microbial degradation, and sorption (61,62), although it is possible that sorption may protect an enzyme from microbial degradation or chemical hydrolysis and retain its activity. The nature of most enzymes, particularly size and charge characteristics, is such that they would have very low mobility in soils, so that if a secreted enzyme is to have any effect, it must operate close to the point of secretion and its substrate must be able to diffuse to the enzyme. Secretory acid phosphatase was found to be produced in response to P-deficiency stress by epidermal cells of the main tap roots of white lupin and in the cell walls and intercellular spaces of lateral roots (63). Such apoplastic phosphatase is safe from soil but can be effective only when presented with soluble organophosphates, which are often present in the soil. solution (64). However, because the phosphatase activity in the rhizo-sphere originates from a number of sources (65), mostly microbial, and is much higher in the rhizosphere than in bulk soil (66), it seems curious that plants would have a need to secrete phosphatase at all. 

J. Wasaki, M. Ando, K. Ozawa, M. Omura, M. Osaki, H. Ito, H. Matsui, and T. Tadano, Properties of secretory acid phosphatase from lupin roots under phosphorus-deficient conditions, Plant Nutrition for Sustainable Food Production and Environment (T, Ando, K. Fujita, T. Mae, H. Matsumoto, S. Mori, and J. Sekiya, eds), Kluwer Academic Publishers, Dordrecht, 1997, p. 295. 

H. Sakai and T. Tadano, Characteristics of respon.se of acid phosphatase secreted by the roots of several crops to various conditions in the growth media. Soil Sci. Plant Nutr. 39 431 (1993). 

B. Dindelaker and H. Marschner, In vivo demonstration of acid phosphatase activity in the rhizosphere of soil-grown plants. Plant Soil 144 99 (1992). 

M. C. Lemoine, V. Gianinazzi-Pearson, S. Gianinazzi, and C. J. Straker, Occurrence and expression of acid phosphatase of Hymeno.scypbus ericae (Read) Korf and Kernan, in isolation or as.sociated with plant roots. Mycorrhiza l 31 (1992). 

Viveros A, Centeno C, Brenes A, Canales R and Lozano A (2000), Phytase and acid phosphatase in plant feedstuffs , J Agric Food Chem, 48, 4009-4013. 

Nuruzzaman H, Lambers H, Bolland MDA, Veneklaas EJ (2006) Distribution of carboxylates and acid phosphatase and depletion of different phosphorus fractions in the rhizosphere of a cereal and three grain legumes. Plant Soil 281 109-120 Olde Venterink H, Wassen MJ, Belgers JDM, Verhoeven JTA (2001) Control of environmental variables on species density in fens and meadows importance of direct effects and effects through community biomass. J Ecol 89 1033-1040. doi http //www.blackwell-synergy.com/ doi/abs/10.111 l/j.1365-2745.2001.00616.x... 

Purple acid phosphatase (PAP) or tartrate-resistant phosphatase is not thought to be a protein phosphatase but it has a very similar dimetallic active site structure to that found in protein phosphatases. PAPs have been identified in bacteria, plants, mammals, and fungi. The molecular weights (animal 35 kDa, plant 55 kDa) are different and they exhibit low sequence homology between kingdoms but the residues involved in coordination of the metal ions are invariant. " There has been considerable debate as to the identity of the metal ions in PAPs in vivo. Sweet potato, Ipomoea batatas, has been shown to possess two different PAP enzymes and the active site of one of them has been shown to contain one Fe and one Zn " " ion. Another report has established that the active site of a PAP from sweet potato contains one Fe " and one Mn +. The well-characterized red kidney bean enzyme and the soybean enzyme contain Fe " and Zn. Claims that PAP from sweet potato has 2Fe ions or 2Mn ions have been discussed elsewhere. One explanation is that these are different forms of the enzyme, another is that because the metal ions are labile and are rapidly incorporated into the active site, the enzyme contains a mixture of metal ions in vivo and the form isolated depends on the conditions of isolation. 

The lysosomes are the cell s stomach, serving to break down various cell components. For this purpose, they contain some 40 different types of hydrolases, which are capable of breaking down every type of macromolecule. The marker enzyme of lysosomes is acid phosphatase. The pH optimum of lysosomal enzymes is adjusted to the acid pH value and is also in the range of pH 5. At neutral pH, as in the cytoplasm, lysosomal enzymes only have low levels of activity. This appears to be a mechanism for protecting the cells from digesting themselves in case lysosomal enzymes enter the cytoplasm at any time. In plants and fungi, the cell vacuoles (see p. 43) have the function of lysosomes. 

Some acid phosphatases from animals and plants are violet in color and contain iron (Chapter 16) and an Mn3+-containing acid phosphatase has been isolated from sweet potatoes.720 These enzymes have dimetal centers, often containing one Zn2+ and one Fe3+ with bridging carboxylate and hydroxide ions between the metals. Imidazole, tyrosinate, and carboxylate side chains hold the metals as in Fig. 16-20. A water molecule bound to the Fe3+ is thought to dissociate with a low pKa of 4.8 to give an Fe3+ OH complex. The hydroxyl ion can then attack the phospho groups, one... 

Kilsheimer and Axelrod have shown that the stereospecific inhibition by d-(+)-tartrate of certain acid phosphatases is widespread. In a wide phylogenetic study, they found that unequivocal plants lack and unequivocal animals possess phosphatases inhibitable by D-tartrate. This rule seems to hold even though all animal acid phosphatases were not inhibited (44)-... 

Purple, iron-containing acid phosphatases have been purified from animal sources and from some plant sources.350 However, the purple acid phosphatase from the sweet potato contains manganese, the purple colour arising from an intense absorption band at about 515 nm. There is some doubt over the stoichiometry, in that the dimeric enzyme may contain one351 or two352 Mn2+, apparently depending on the variety of sweet potato. The iron acid phosphatases contain two Fe atoms. 

Other enzymes capable of halogenation processes include a bacterial esterase from Pseudomonas fluorescens (2316), acid phosphatases from the bacteria Shigella flexneri and Salmonella enterica ser. typhimurium (2317), a lactonohydrolase from Acinetobacter calcoaceticus F46 (2318), and hydroperoxide halolyse from the marine diatom Stephanopyxis turris (2319). The biosynthesis of the ubiquitous methyl halides seems to involve methyl transferase enzymes, which have been isolated and purified in the plant Brassica oleracea (S -adenosyl-L-methionine ... 

Phosphate starvation inducible acid phosphatases in higher plants... 

Ninomiya, Y., Ueki, K. Sato, S. (1977). Chromatographic separation of extracellular acid phosphatase of tobacco cells cultured under Pi-supplied and omitted conditions. Plant and Cell Physiology 18, 413-20. 

Paul, E.M. Williamson, V.M. (1987). Purification and properties of acid phosphatase-1 from a nematode-resistant tomato cultivar. Plant Physiology 84, 399-403. 

Jacobson, A. and Corcoran, M. R. 1977. Tannins as gibberellin antagonists in the synthesis of a-amylase and acid phosphatase by barley seeds. Plant... 

Phytase (Aspergillus niger var.) Produced as an off white to brown powder or as a tan to dark brown liquid by controlled fermentation using Aspergillus niger var. Soluble in water, but practically insoluble in alcohol, in chloroform, and in ether. Major active principles (1) 3-phytase and (2) acid phosphatase. Typical applications used in the production of soy protein isolate and in the removal of phytic acid from plant materials. 

Similar Mn-containing enzymes were subsequently isolated from other plant sources spinach leaves (71), rice plant cultured cells (72), soybeans (73-75), and the tubers of the sweet potato Kintoki (76-81) (Table III). Sweet potatoes have recently been reported to possess two different acid phosphatases which were immunologically distinct but which have similar molecular weights and metal content (106). Interestingly, sulfhydryl reagents have been shown to inactivate the soybean enzyme (75). 

The presence of Mn in the naturally occurring acid phosphatase has been questioned (82). The electronic spectra of these plant enzymes are extremely similar to those of mammalian enzymes which contain two... 

Hegeman, C.E., and Grabau, E.A., 2001, A novel phytase with sequence similarity to purple acid phosphatases is expressed in cotyledons of germinating soybean seedlings. Plant Physiol. 126 1598-1608. 

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