Acid phosphatase bovine

Figure 1. Characteristic EPR signals of Fe(II)Fe(III) sites in semimethemerythrinj (a), semimethemerythrinQ (b), reduced uteroferrin (c), reduced uteroferrin-molybdate complex (d), reduced bovine spleen purple acid phosphatase (e), reduced component A of methane monooxygenase (f). (Reproduced with permission from ref. 26. Copyright 1987 Elsevier.)...

Lakritz et al. (32) reported that radiation doses of less than 10 kGy (at 0 to 4 C) produced minimal changes in the micro structure of bovine longissimus dorsi muscle. At doses of 30 kGy or higher, myofibril fragmentation and decreased tensile strength were noted. Lakritz and Maerker (33) reported reductions of 8% and 42% in the activities of lysosomal enzymes and acid phosphatase of irradiated (10 kGy) bovine longissimus dorsi muscle tissue. 

Solutions of acid phosphatase are particularly sensitive to surface inactivation. Figure 3 (88) shows the inactivation rate of the enzyme in the presence and absence of surface-active detergents. The inactivation process is temperature sensitive and the protection by detergent is total. Most of the enzyme inactivation proceeds with first-order kinetics. A variety of agents—gelatin, bovine serum albumin, egg albumin, and Tween-80—protect the enzyme against inactivation. 

A number of purple acid phosphatases821 have been isolated from animal sources, including bovine spleen, rat bone and the enamel organ of rat molars. Other phosphatases may belong to this class but the identification is not yet certain. Purple acid phosphatase from the sweet potato, as noted in Section 62.1.3.6.1, contains manganese. 

Various kinetic studies of the bovine spleen acid phosphatase have been reported (Vincent etal., 1991). The results are consistent with a picture in which the oxyanions bind in a non-competitive fashion by bridging the two iron atoms in the PAP s dinuclear centre, with the smaller anions also able to bind in a competitive manner at a second site (Fig. 5-21). 

The purification of acid phosphatase from the human liver and the description of its properties do not appear to have been accomplished. Partly, this may be due to the inherent difiBculty of obtaining normal, fresh human material in amounts substantial enough for purification. However, because of the cellular and physiological importance of acid phosphatase, it is advisable to describe in the present section the purifications of the enzyme from rat and bovine liver. Moreover, since these purifications were accomplished with the awareness that acid phosphatase from this source might be present in multiple molecular forms, the descriptions will naturally involve a consideration of the isoenzymes and their properties. 

The solution was divided into two 40-ml portions, and each portion was added to a column of Sephadex G-75 that had been equilibrated with 0.01 M sodium acetate, 1 mM EDTA, pH 4.8. Elution was continued in the same buffer. Gel filtration of a crude extract of bovine liver on Sephadex-75 had previously given two small peaks and a third large peak of acid phosphatase activity. Elution of the purified 35-50% ammonium sulfate fraction now gave a small peak of about 10% of the enzyme activity, no second peak, and a third peak that contained 90% of the enzyme. The third peak (acid phosphatase III) represented the low molecular weight component and constituted 30% of the total acid phosphatase present in the 15,000g supernatant starting material the degree of purification was 54-foId. 

H3. Heinrikson, R. L., Purification and characterization of a low molecular weight acid phosphatase from bovine liver. J. Biol. Chem. 244, 299-307 (1969). 

VI-IX are structurally characterised, vanadate-inhibited phosphatases. VI, Rat prostat acid phosphatase VII, bovine phosphotyrosyl phosphatase VIII, mammalian protein tyrosine phosphatase PTP-IB (mutant Cys215Ser) IX, E. coli alkaline phosphatase. For comparison, the active centre of vanadate-dependent haloperoxidases (VHPO) (V), is also shown. The structures Xa and Xb have been proposed, based on EPR, for the vanadyl complexes formed with the PTP-IB active site peptide Val-His-Cys-Ser-Ala-Gly. 

Ramponi G, Manao G, Camici G et al (1989) The 18 kDa cytosolic acid phosphatase from bovine live has phosphotyrosine phosphatase activity on the autophosphorylated epidermal... 

The purple acid phosphatases (PAP) catalyze the hydrolysis of phosphate esters under acidic pH conditions (pH optimum 5) (9, 10). They differ from other acid phosphatases in having a distinct purple color due to the presence of iron or manganese and in being uninhibited by tartrate. Diiron units have been found in the active sites of the enzymes from mammalian spleen (171-173) and uterus (173, 174), while a heterodinu-clear FeZn unit has been characterized for the enzyme from red kidney bean (175). Either the Fe2 or the FeZn unit is catalytically competent in these enzymes, since the enzymes from porcine uterus and bovine spleen can be converted into active FeZn forms and the kidney bean enzyme can be transformed into an active Fe2 form (176). There are also enzymes from other plant sources (particularly sweet potato) that have been reported to have either a mononuclear Mn(III) or Fe(III) active site (177), but these are beyond the scope of the review. This section will focus on the enzymes from porcine uterus (also called uteroferrin), bovine spleen, and red kidney bean. 

The purple acid phosphatases can occur in two diferric forms—one as the tightly bound phosphate complex (characterized for the bovine and porcine enzymes) (45, 171, 203) and the other derived from peroxide or ferricyanide oxidation of the reduced enzyme (thus far accessible for only the porcine enzyme) (206). These oxidized forms are catalytically inactive. They are EPR silent because of antiferromagnetic coupling of the two Fe(IIl) ions and exhibit visible absorption maxima near 550-570 nm associated with the tyrosinate-to-Fe(III) charge-transfer transition. The unchanging value of the molar extinction coefficient between the oxidized and reduced enzymes indicates that the redox-active iron does not contribute to the visible chromophore and that tyrosine is coordinated only to the iron that remains ferric in agreement with the NMR spectrum of Uf, (45). 

Several bioactive proteins retained their activity and conformation in sol-gel matrices. The sol-gel entrapped heme proteins such as cytochrome c and Mb showed good stability against pH and thermal perturbations compared to protein in solution [29, 55]. The sol-gel caged cytochrome c (cyt c) showed high thermal stability due to the exact fitting of the protein inside the cage, which was controlled by the protein size [56]. Sol-gel encapsulated acid phosphatase [57] and bovine carbonic anhydrase II (BCA II)... 

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