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W Ostrowski

Publications and source records attributed to W Ostrowski.

At least 19 recordsLinked to original sources
PubMed1990

Is the subunit of prostatic phosphatase active? Reversible denaturation of prostatic acid phosphatase.

Prostatic acid phosphatase [E.C. 3.1.3.2.] is a dimeric protein consisting of two identical subunits. This enzyme was denatured in 6 M urea solution at pH 2.5, and kinetical analysis of reactivation by dilution was performed. At low protein concentrations a second-order kinetics for reactivation of phosphatase, with rate constant 8.3 m M-1sec-1, was observed. At higher protein concentrations the reactivation obeyed first-order kinetics. These results seem to exclude the possibility that subunits of the prostatic phosphatase are catalytically active and suggest that the association of two monomers is necessary for full activity.

Acid Phosphatase↗
PubMed1980

Properties of low-molecular-weight acid phosphatases isolated from cytosol and chromatin of rat liver.

1. Acid phosphatases (orthophosphoric-monoester phosphohydrolases, acid optimum, EC 3.1.3.2) of low molecular weight were isolated from cytosol and chromatin of rat liver cells. The cytosolic enzyme was homogeneous on SDS-polyacrylamide-gel electrophoresis at pH 8.3 (mol. wt. 16 000+/-3000). Both enzymes showed similar electrophoretic mobility and molecular weight but they differed in substrate specificity, response to inhibitors and susceptibility to SH-protecting reagents.

Acid Phosphatase↗
PubMed1978

Isolation of tau-phosphohistidine from a phosphoryl-enzyme intermediate of human prostatic acid phosphatase.

The carbethoxylation of prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) was accompanied by modification of histidine residues and the inactivation of the enzyme. These findings are consistent with photoinactivation experiments described earlier (Rybarska, J. and Ostrowski, W (1974) Acta Biochim, Polon. 21, 377--390). Prostatic acid phosphatase was phosphorylated at alkaline pH using p-nitrophenyl [32P]phosphate as substrate. Phosphoryl enzyme is stable in alkaline solutions and undergoes dephosphorylation at acidic pH. After hydrolysis of phosphoryl enzyme in strong alkaline solution, a single phosphoryl amino acid was isolated from hydrolyzate and identified as the tau-phosphohistidine.

Acid Phosphatase↗
PubMed1977

Comparative studies on immobilization of human prostatic acid phosphatase.

Acid phosphatase (othophosphoric monoester phosphohydrolase (acid optimum), EC 3.1.3.2) from the human prostate was immobilized by its protein moiety on cyanogen bromide-activated Sepharose, by carbohydrate moiety on Concanavalin-A-Sepharose, and by Schiff base formation with partially oxidized carbohydrate groups on ethylenediamine-Sepharose. The highest retention of enzyme activity, 80%, was found for the noncovalent immobilization on Concanavalin-A-Sepharose. It was demonstrated that the optimal pH changes for the Concanavalin-A-Sepharose and CNBr-Sepharose-enzyme complexes are electrostratic in character. In all cases of immobilization the enzyme has higher thermostability than that for the native enzyme under the same conditions. The effects of the enzyme stabilization were interpreted in terms of the multipoint interaction between the enzyme molecule and the carrier.

Acid Phosphatase↗
PubMed1976

Acid phosphomonoesterase of human prostate. Carbohydrate content and optical properties.

Human prostatic acid phosphatase I, a glycoprotein, has been analyzed with respect to its quantiative carbohydrate composition and its fluorescence, optical rotatory and circular dichroic spectra. The protein of 89 000 molecular weight has 38 to 41 carbohydrate residues attached, of which 3 residues are fucose, 4 are galactose, 11 mannose, 15 glucosamine and there are 7 to 8 residues of sialic acid. The native glycoprotein contains about 30% alpha-helix as estimated from the rotational and dichroic spectra. Upon removal of sialic acid by neuraminidase treatment, there is a small increase in this value, while the fluorescence intensity at he emission maximum (357 nm) is distinctly increased. These effects suggest that an interaction exists of the sialic acid group with parts of the native protein. Allowance is made for the contribution of the carbohydrate components in interpreting the spectra in structural terms.

Acid Phosphatase↗
PubMed1976

Alkaline phosphatase of Thiobacillus thioparus. Partial purification and properties of the enzyme.

Soluble alkaline phosphatase from Thiobacillus thioparus cells was purified about 230-fold. The enzyme had a mol. wt. of 50 000 daltons, optimum pH at 10.5, and was heat-resistant in the presence of diethanolamine. Polyacrylamide-gel electrophoresis demonstrated contamination of the preparation with inactive proteins and the presence of two active bands. The enzyme activity was distinctly stimulated by increasing concentrations of Tris or diethanolamine. In the presence of glycine, 1 mM-Zn2+ enhanced the enzyme activity; in Tris or diethanolamine buffers the activity was stimulated by 1 mM-Mg2+ whereas Zn2+ had a strong inhibitory effect. Glycine at concentrations exceeding 25 mM also inhibited the enzyme. Specificity of the enzyme is fairly broad.

Alkaline Phosphatase↗
PubMed1975

Preparation and characterisation of ribonuclease from human hypertrophic prostate gland (RNAase P2).

An endo-type, cyclising, 3'-phosphate-forming rebonuclease was purified to homogeneity from a water/Tween 80 extract of human hypertrophic prostate gland. The enzyme is acid- and heat- resistant and is optimally active at pH 7.0, 0.1 M NaCl. Molecular weight determined by gel filtration on Sephadex G-75 and sucrose density gradient centrifugation gave a mean value of 15 000. The prostatic ribonuclease is inhibited by Cu2+, bromoacetate and photooxidation in the presence of methylene blue. Other divalent ions, EDTA and p-chloromercuribenzoate have no influence on the enzymic activity. Prostatic RNase resembles RNase A in that it preferentially cleaves linkages in RNA after pyrimidine nucleotides to produce oligonucleotides terminated in cyclic 2',3' phosphate. The enzyme is inactive with poly(A) - poly(U) as substrate. Poly(U) is hydrolyzed four times as fast as poly(C), and 1.2 times as fast as RNA.

Cations, Divalent↗
PubMed1975

The role of tryptophan residues and hydrophobic interaction in the binding of riboflavin in egg-yolk flavoprotein.

Egg-yolk flavoprotein has 7.2 tryptophan residues exposed, while the apoprotein shows an apparent exposure of 80 percent of these (5.7 residues) with dimethylsulphoxide as the perturbant. In the apoprotein at pH 6.9 only 4 groups are perturbed to ethylene glycol, 3.2 to glycerol and 1.4 to sucrose. Diminishing estimates of exposure obtained with increasing molecular diameter of the perturbant suggests that part of indole chromophores of apoprotein are located in "crevices" of the protein molecule. The apoprotein was treated with 2-hydroxy-5-nitrobenzyl bromide, H2O2 and N-bromosuccinimide under conditions designed to accomplish modification of tryptophan residues. Five to six of the eight tryptophans present in the protein were modified. Under these conditions the apoprotein completely looses its capacity for binding riboflavin and the fluorescent intensity of the protein at 360 nm is quenched at the same time to about 80 percent of its initial value. The presence of nonpolar amino acid residues on the surface of the apoprotein suggested the importance of hydrophobic interactions as the dominant factor controlling the binding of riboflavin. The hydrophobic probes Indocyanine green and 4-benzoylamide-4-aminostilbene-2,2-disulphonic acid bound to the apoprotein giving equimolar complexes with dissocation constants, KD 6.5-10(-7) M and 1.8-10(-6) M, respectively, Addition of an equimolar amount of riboflavin quantitatively displaced these dyes from their complexes with apoprotein as shown by spectrophotometric and spectrofluorometric studies.

Amino Acids↗