Acid phosphatase distribution

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... 

Acid phosphatase is widely distributed in tissues. Male prostate glands7 are extraordinarily rich, and this enzyme is implicated in the physiology of sex. Men excrete in the urine about 3.5 times as much... 

Phosphates of pharmaceutical interest are often monoesters (Sect. 9.3), and the enzymes that are able to hydrolyze them include alkaline and acid phosphatases. Alkaline phosphatase (alkaline phosphomonoesterase, EC 3.1.3.1) is a nonspecific esterase of phosphoric monoesters with an optimal pH for catalysis of ca. 8 [140], In the presence of a phosphate acceptor such as 2-aminoethanol, the enzyme also catalyzes a transphosphorylation reaction involving transfer of the phosphoryl group to the alcohol. Alkaline phosphatase is bound extracellularly to membranes and is widely distributed, in particular in the pancreas, liver, bile, placenta, and osteoplasts. Its specific functions in mammals remain poorly understood, but it seems to play an important role in modulation by osteoplasts of bone mineralization. 

Chronic in vivo hemolysis produces serum lactic dehydrogenase elevations in patients with mitral or atrial valve cardiac prosthesis (J2). In a series of 11 such patients these increases ranged from 1.1 to 1.6 times the upper limit of normal (S29). Blood pH is altered in hemolyzcd specimens because carbonic anhydrase is liberated from the erythrocytes and presumably alters the distribution of H2CO3 and NaHCOs (B2). Hemolysis will effect acid phosphatase activity if the substrate is hydrolyzed by erythrocyte acid phosphatase. Thus, hemolysis would be of concern if phenyl phosphate was the substrate, but would have a negligible effect if )8-glycerophosphate, which is not hydrolyzed by red cell acid phosphatase, was used (Bl). 

Beckman et al. (28) have studied the electrophoretic separation of the acid phosphatase activity in tissue extracts on starch gel at pH 8. They described four electrophoretic bands A, B, C, and D. Table IV (28) shows the distribution of activity in different organ extracts. The ABD pattern predominated in kidney BD in liver, intestine, heart, and skeletal muscle B in skin and D in pancreas. The C component was present in a large number of placentae but not in other adult organs. All four electrophoretic components were inhibited by d-(- -)-tartrate A contained sialic acid, D had a lower pH optimum and was more heat resistant than A, B, and C. Components C and D showed parallel electrophoretic behavior. In human skin fibroblasts grown in tissue culture, the acid phosphatase was generally high and the most common pattern was BD. Almost every culture showed some activity. The BD... 

Distribution of Acid Phosphatase Components in the Tissues of 14 Different Individuals0 6... 

Fig. 13. The distribution of red cell acid phosphatase activities in a randomly selected English population (dotted line) and in the separate phenotypes. From Hopkinson and Harris (85).

De Jong, D.W. (1965). Histochemical demonstration of extracellular distribution of acid phosphatase in onion roots. Phyton 22, 141-6. 

Nakanishi, T., Tagata, Y. 1972. The distribution and some properties of esterase, alkaline phosphatase and acid phosphatase in cow s milk. Jap. J. Dairy Sci. 21, A-207-215. 

Figure 9-14. Frequency distribution of various marker enzymes for lysosomes (acid phosphatase, cathepsin, etc.), peroxisomes (urate oxidase) and mitochondria (cytochrome oxidase). Mitochondrial fraction from rat liver centrifuged in a linear gradient of 0.25 to 0.5M sucrose. [From H. Beaufay et al., Biochem. /., 73 628 (1959).]...

Study of the distribution of acid phosphatase in different tissues is burdened by indications that there are several acid phosphatases. Even the older literature indicated the nonidentity of acid phosphatases of different origin. In 1934, Davies (D4) showed that the acid phosphatase in the red cell hydrolyzed a-glycerophosphate more readily than )8-glycerophosphate, whereas the reverse was true for the acid phosphatase from spleen. Kutscher and Wolbergs (K12) found that prostatic acid phosphatase was inactivated irreversibly by various narcotics, including alcohols. 

An approximate idea of the distribution of acid phosphatase activity in human tissues, regardless of the nature of the acid phosphatase, may be obtained from the studies of Reis (R2) on 5 -nucleotidase and other phosphomonoesterases. He prepared aqeuous homogenates of postmortem tissue in the proportion of 20 parts of water to one of tissue, allowed these to autolyze for 2 days at room temperature, centrifuged the material, and employed the supernatant fluid. The assay mixture consisted of 0.4 ml of a suitable buffer, 0.1 ml of 0.005 Af phenyl phosphate as substrate, and 0.1 ml of tissue extract. The enzyme activity was expressed as micrograms of phosphorus hydrolyzed per hour per milligram of wet... 

The purification of acid phosphatase from the human prostate was undertaken, and high degrees of purity were obtained, before any solid information was available concerning the intracellular distribution of this enzyme or its existence in multiple molecular forms or isoenzymes. Accordingly, in this review several methods of purification will be described first, and the other aspects will then be considered. 

The acid phosphatase appeared to be associated in the saclike structure with other hydrolytic enzymes, such as 3-glucuronidase and cathepsin, which also acted optimally at acid pH levels. Further studies were undertaken to isolate this structure (A13, G2). By means of a differential centrifugation procedure which will be described in detail later, de Duve and his associates (D9, DIO) determined the intracellular distribution of total and free acid phosphatase activity and of other enzymes as well. The mean values, expressed as percent of total acid phosphatase activity, were nuclear, 3.6 mitochondrial, 24.1 light mitochondrial, 40.7 microsomal, 20.1 final supernatant, 13.3. 

Of several methods that are potentially available for determining the intracellular distribution of acid phosphatase and other enzymes, the chief ones currently in use are ultracentrifugal separation and histochem-ical examination. Each of these has its disadvantages and advantages, some of which have already been indicated. At this point we will consider the quantitative ultracentrifugal methods. 

The yield of acid phosphatase was 11%, as compared with 30% for aryl sulfatase and 15% for ribonuclease. Obviously, in the attempt to obtain pure preparations of intracellular components, it is inevitable that losses be encountered. Such procedures are therefore not suited for obtaining an estimate of the quantitative distribution of intracellular components. Approximately 5-9% of the lysosomal enzymes—aryl sulfatase, acid phosphatase, and ribonuclease—were present in the free form. The remaining 91-95% of the activities of these enzymes were in the latent form and required alteration of the permeability or disruption of the lysosomal membrane to become active. 

It has been estimated that approximately 70-80% of the acid phosphatase in rat liver can be recovered in the lysosomal fraction, the remainder being distributed between the soluble fraction and other sub-cellular fractions (D9, S15). The question therefore arises concerning the extent to which this remainder is derived from lysosomes broken during the fractionation procedure or whether some acid phosphatase is actually localized in subcellular structures, other than lysosomes. 

Intracellular Distribution of Acid Phosphatase in Other Tissues... 

Most of our knowledge of lysosomes arises from studies of these particles in rat liver. These studies have also supplied considerable evidence that, by virtue of its more than a dozen hydrolytic enzymes, the lysosome can play a role in digesting material foreign to the cell, its own cell, or that its enzymes may be discharged outside the cell to produce lytic effects. It is also possible, as has been shown for rat liver (Rl), that lysosomes may be heterogeneous in terms of their enzyme contents. We shall now examine the extent to which acid phosphatase is distributed intracellularly in tissues other than the liver and in species other than the rat. 

The centrifugal method of separation employed by Van Lancker and Holtzer (V2) was among the earlier ones in the field, and there was probably considerable cross contamination of the fractions. Nonetheless, the distribution seems more disperse than that obtained by de Duve et al. (DIO) for rat liver with a comparable method. For example, in the case of the mouse pancreas the small mitochondrial fractions, c, d, and e, obtained by centrifugation between 17 X 10 and 263 X 10 gr-min contained 27% of the acid phosphatase and the succeeding microsomal fractions, f and g, obtained by centrifugations between 263 X 10 g-min and 3170 X 10 g-min, contained 24% of the acid phosphatase (V2). For rat liver, comparable fractions, obtained by centrifugation between 33 X 10 to 250 X 10 g-min and 250 X 10 to 3000 X 10 g-min contained 41 and 20%, respectively (DIO). 

Attempts to determine the intracellular distribution of acid phosphatase in the prostate must take into account the presence of this enzyme in the extracellular secretion. Employing centrifugal methods, Siebert et al. (S20) found that of the total acid phosphatase present in bull prostate homogenate, 0.7% was in the nuclear fraction, 41% in the mitochondrial fraction which presumably included the lysosomal component, and 84% in the microsomal and supernatant components. The finding that the sum of these activities exceeded that in the homogenate was considered to represent removal of inhibitors during separation of the fractions. 

The intracellular distribution of acid phosphatase in the ventral prostate of the rat has also been investigated by Bertini and Brandes (B15). Groups of male rats of two weight levels, 350 20 g and 180 10 g... 

The character of the intracellular distribution of acid phosphatase in the testis appears to differ from that in the kidney or liver, where a major portion of the enzyme is in the lysosomal fraction. Although the finding in the testis may represent a difference in cellular organization, the possibility also exists that the acid phosphatase may be less firmly bound to the lysosomal structure in the testis than in the liver and may be more readily solubilized during the process of homogenization. 

---