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A Kubicz

Publications and source records attributed to A Kubicz.

At least 19 recordsLinked to original sources
PubMed1999

A novel 35 kDa frog liver acid metallophosphatase.

The lower molecular weight (35 kDa) acid phosphatase from the frog (Rana esculenta) liver is a glycometalloenzyme susceptible to activation by reducing agents and displaying tartrate and fluoride resistance. Metal chelators (EDTA, 1,10-phenanthroline) inactivate the enzyme reversibly in a time- and temperature-dependent manner. The apoenzyme is reactivated by divalent transition metal cations, i. e. cobalt, zinc, ferrous, manganese, cadmium and nickel to 130%, 75%, 63%, 62%, 55% and 34% of the original activity, respectively. Magnesium, calcium, cupric and ferric ions were shown to be ineffective in this process. Metal analysis by the emission spectrometry method (inductively coupled plasma-atomic emission spectrometry) revealed the presence of zinc, iron and magnesium. The time course of the apoenzyme reactivation, the stabilization effect and the relatively high resistance to oxidizing conditions indicate that the zinc ion is crucial for the enzyme activity. The presence of iron was additionally confirmed by the visible absorption spectrum of the enzyme with a shoulder at 417 nm and by the electron paramagnetic resonance line of high spin iron(III) with geff of 2.4. The active center containing only zinc or both zinc and iron ions is proposed. The frog liver lower molecular weight acid phosphatase is a novel metallophosphatase of lower vertebrate origin, distinct from the mammalian tartrate-resistant, purple acid phosphatases.

Acid Phosphatase↗
PubMed1999

Alterations of the sugar moiety of Tamm-Horsfall protein in children with malignancies of lymphoid cells.

The aim of this study was to examine whether the sugar moiety of Tamm-Horsfall protein (THP) is affected by pathological processes caused by acute lymphoblastic leukemia (ALL) or non-Hodgkin's lymphoma (NHL). The carbohydrate part of THP was studied by monosaccharide analysis, N-glycan profiling, and reactivity with specific lectins. Our results have shown that THP of ALL or NHL patients, in comparison with healthy subjects, have modified sugar chains. This is expressed in lower contents of N-acetylgalactosamine, alpha2,6-linked sialic acid and alpha1,6-linked fucose as well as in altered proportions of various N-glycans. We have shown that pathological processes also affect the carbohydrate unit of human immunoglobulin G (IgG) isolated from sera of ALL or NHL patients. As compared with healthy subjects, in IgG of the patient group, lower amounts of sialic acid and fucose were observed. These changes did not influence the biological properties of THP as judged by their unaltered ability to bind with interleukin-1alpha, alpha1-acid glycoprotein, serum albumin, transferrin, IgG1 and the light and heavy chains of IgG. Neither the in vivo alterations of IgG caused by ALL or NHL nor its in vitro modifications influence the interaction between IgG and THP.

Adolescent↗
PubMed1999

Composition of the sugar moiety of Tamm-Horsfall protein in patients with urinary diseases.

The sugar moiety of Tamm-Horsfall protein (THP) is altered by pathological conditions. The aim of this study was to investigate the composition of THP glycans in urinary diseases. THP was isolated from the urine of patients with urinary tract infection (group A), glomerulonephritis or interstitial nephritis (group B), and Bartter's syndrome (BS) (group C). Monosaccharides, N-glycan profile, THP reactivity with specific lectins and some other proteins were analyzed. THP of patients from groups A, B, and C showed lower amounts of N-acetylgalactosamine (P<0.05, P<0.005, and P<0.05, respectively) than controls; this was reflected in lower reactivity with Phaseolus vulgaris lectin (P<0.005, P<0.05, and P<0.005). Reduced amounts of N-acetylglucosamine were noticed in groups A (P<0. 05) and B (P<0.05). In group A lower amounts of galactose and alpha2, 6-linked sialic acid, as determined by reactivity with Datura stramonium lectin (P<0.005) and Sambucus nigra lectin (P<0.005), were observed. In patients with BS there was a shift from tetrasialylated glycans towards less-sialylated chains. We found also that THP of all patients binds more strongly to IgG(1) (P<0.005, for all patient groups). Our results indicate that the urinary diseases examined affect the THP sugar moiety and the binding of THP to IgG(1).

Acetylglucosamine↗
PubMed1999

The sugar moiety of Tamm-Horsfall protein is affected by the carbohydrate-deficient glycoprotein type I syndrome. A case study.

As the sugar moiety of Tamm-Horsfall protein (THP) is affected by many pathological conditions, the aim of this study was to examine the influence of carbohydrate-deficient glycoprotein syndrome (CDG) on THP glycans. THP was isolated from urine of one patient with CDG type I and N-glycan profiling, analysis of monosaccharide content, determination of THP reactivity with specific lectins and with anti-THP antibodies were performed. THP of the CDG patient showed markedly lower amounts of all monosaccharides. Diminished amounts of lactosamine-type chains, galactose and alpha2,3 linked sialic acid were expressed in lower reactivity with PHA-L, DSA and MAA, respectively. These modifications were reflected in altered proportions of tetrasialylated and disialylated oligosaccharide chains. THP of the CDG patient reacted slightly more with anti-THP antibodies. Our results indicate that the CDG type I affects the THP sugar moiety and slightly enhances the THP immunoreactivity.

Blotting, Western↗
PubMed1998

Tamm-Horsfall protein isolated from urine of pregnant and non-pregnant women has similar oligosaccharides.

BACKGROUND: Differences in the immunosuppressive activity of Tamm-Horsfall protein and uromodulin claimed by many investigators are controversial. They have been ascribed to variations in the carbohydrate moiety. METHODS: We isolated urinary glycoproteins from 18 non-pregnant (THP) and 12 pregnant (UM) women using the same method (adsorption on diatomaceous earth) and performed comparative studies including monocarbohydrate analysis and tests of reactivity with lectins, cytokines and serum proteins. RESULTS: No significant differences in monocarbohydrate content or in the reactivity with specific lectins were found between the native urinary glycoproteins or between their proteolytic products. Also, in Sda+ and Sda- donors monitored throughout pregnancy and after delivery, no time-dependent differences in the sugar moiety were observed. We found that THP/UM from Sda+ donors reacted more strongly with PHA-L than THP/UM from Sda- donors, providing further evidence for carbohydrate variations between Sda+ and Sda- determinants. No differences between THP and UM in terms of their reactivity with recombitant human interleukin (rhIL) 1 alpha, recombinant human tumour necrosis factor (rhTNF) alpha and some serum proteins were found, indicating similar biological activity. CONCLUSION: The results of our carbohydrate analysis together with previous data on amino acid analysis indicate that Tamm-Horsfall protein and uromodulin are identical or very similar glycoproteins.

Adult↗
PubMed1997

The 102 kDa chicken liver acid phosphatase: dimeric structure, glycoprotein nature and immunological properties.

In this study we isolated a highly purified, homogeneous high molecular weight (HMW) AcPase (Mr 102 kDa) from the chicken liver. This enzyme was shown to be a slightly acidic (pI 5.0-6.1), dimeric sialoglycoenzyme, composed of two equivalent subunits. Its sugar moiety, characterized by interactions with specific lectins, was shown to be composed of hybrid and complex type of carbohydrate chains. Heterogeneity of the high molecular weight AcPase arising from variations of the sugar components was demonstrated by isoelectric focusing, followed by reactions of the isoelectric components with specific lectins on NC membranes. Structural relationship based on immunological similarities was shown between the HMW AcPases from carp, frog, and chicken livers.

Acid Phosphatase↗
PubMed1996

Alterations of Tamm-Horsfall protein immunoreactivity after partial desialylation and deglycosylation.

The role of the carbohydrate moiety of Tamm-Horsfall protein (THP) was investigated by studying the effect of partial enzymatic desialylation and deglycosylation on its immunoreactivity. In our experiments primarily sialic acid alpha 2,6 linked to a galactose was split off, resulting in a 14% increase of immunoreactivity. It was increased up to 21% by further removal of the sugar residues. We also found that complexes composed of THP and human serum albumin, immunoglobulin G or transferrin reacted with anti-THP antibodies. When these complexes were formed with desialylated or deglycosylated THP an essential increase of this reactivity (about 25%) occurred. Our studies indicate that modifications of the carbohydrate moiety of THP (which might occur in vivo by changes in the glycosylation process e.g. in pathologic conditions) lead to increased exposure of THP to the immune system.

Animals↗
PubMed1993

Characterization of the type of carbohydrate chains of the higher molecular weight (140 kDa) acid phosphatase of the frog liver.

1. The higher molecular weight, (HMW, M(r) 140 kDa) acid phosphatase (AcPase) of the frog liver (Rana esculenta) was separated into enzymatically active components by isoelectric focusing in an immobilized pH gradient and their carbohydrate chains were analyzed by specific lectin binding after native blotting. 2. The lectin-binding patterns obtained with ConA, WGA, LcH and PNA as well as with WGA and PNA after desialylation indicate that the frog liver HMW AcPase contains predominantly N-linked complex and/or hybride type carbohydrate chains with terminal sialic acid and fucose residues; O-glycosylated enzyme components with free and sialic acid substituted Gal-GalNAc sequences were also detected.

Acid Phosphatase↗
PubMed1992

Amino acid composition and immunochemical properties of AcPase III and AcPase IV representing glycoforms of the lower molecular weight, tartrate-resistant acid phosphatase of the frog liver.

1. Amino acid composition and immunological properties of the frog liver LMW AcPase forms: AcPase III and IV were examined. 2. AcPase III and IV show nearly identical amino acid composition and close immunological similarity. 3. These results indicate protein identity of both the enzyme forms and together with our previous data [Kubicz A., Szalewicz A. and Chrambach A., Int. J. Biochem. 23, 413-419 (1991)] demonstrate that generation of AcPase III and IV is a modification of the same enzyme protein by glycosylation processes. 4. Differences in immunoreactivity between AcPase III and IV were observed and discussed to be due to their altered conformations.

Acid Phosphatase↗
PubMed1992

Molecular basis for the functional diversity of enzyme forms of the LMW (Mr 38,000) acid phosphatase of the frog liver.

Recent studies on the structure and function of the tartrate-resistant acid phosphatase (Mr 38,000) of the frog liver are reviewed. The nature of the enzyme heterogeneity is elucidated on a molecular and physiological basis. The following structure-activity relationship is proposed: the enzyme protein is modified by glycosylation processes leading to formation of the different enzyme forms. The oligosaccharide chain stabilizes the final structure of the enzyme forms with altered conformation causing different exposure of the essential functional groups (e.g. sulfhydryl residues, antigen determinants). This leads to different physiological events necessary for fulfillment of metabolic requirements of the cell.

Acid Phosphatase↗
PubMed1991

Studies on the oligosaccharide heterogeneity of the isoelectric forms of the lower molecular weight acid phosphatase of frog liver.

1. The lower molecular weight, heterogeneous acid phosphatase (AcPase) from the frog liver (Rana esculenta) containing AcPase I, II, III and IV was separated into enzymatically active components by isoelectric focusing in an immobilized pH gradient. 2. The blotted enzyme bands were characterized by their different binding patterns obtained with the lectins concanavalin A, wheat germ agglutinin (WGA), Lens culinaris hemagglutinin (LcH) and peanut agglutinin (PNA). 3. In situ neuraminidase treatment reduced the staining intensity of some WGA-bands and increased that of PNA-bands. 4. The finding that AcPases I, II, III and IV differ in their carbohydrate chain composition, together with previous results showing different bioactivities of AcPases III and IV, indicates a correlation between the glycosylation state of enzyme forms and their physiological action.

Acid Phosphatase↗
PubMed1990

Electrofocusing of acid phosphatases from frog liver, using an immobilized pH gradient.

Isoelectric focusing on carrier ampholyte-containing immobilized pH gradient gels was applied (i) to gels submerged in silicone oil on a Peltier cooled apparatus, (ii) to the separation of the higher molecular weight (HMW, Mr 140,000) and the lower molecular weight (LMW, Mr 38,000) acid phosphatases (AcPases) from frog livers. (i) Electrofocusing was conducted on gels submerged under silicone oil cooled and stirred on a Peltier-thermoregulated horizontal gel support plate. This procedure aimed at a) improving the temperature control of the gel by direct contact of coolant with the gel surface, and thus at being able to focus at the maximal field strength and consequently highest resolution; b) preventing evaporation from the gel and c) excluding atmospheric carbon dioxide. Silicone oil submersion did not abolish water loss from the gel into the electrolyte strips during isoelectric focusing, or a rippled gel surface. Absence of water exudation on the ripples noted previously by Atland [1] was observed. (ii) The electrofocusing of AcPases on immobilized pH gradients yielded patterns which remained stationary as a function of time, by contrast to previous analyses on carrier ampholyte generated pH gradients. The total number of enzymatically active components found in the enzyme preparations from different stages of purification and in the isolated HMW and LMW AcPases was 18. The HMW and LMW AcPases focused in characteristic pH ranges and exhibited qualitative and quantitative pattern differences. Their band patterns add up to that of a crude preparation containing both enzymes. Neither polyacrylamide gel electrophoresis (PAGE) at any nondenaturing pH, nor isoelectric focusing in carrier ampholytes with pattern changes due to the pH gradient drift were able to yield that result.

Acid Phosphatase↗
PubMed1989

The lower molecular weight acid phosphatase from the frog liver: isolation of homogeneous AcPase III and IV representing glycoforms with different bioactivity.

1. AcPase III and AcPase IV, the major enzyme forms of the LMW AcPase of the frog (Rana esculenta) liver were resolved and purified to homogeneity. 2. AcPase III and IV showed a single protein band on SDS-PAGE corresponding to a mol. wt (Mr) of about 35,000. The Mr of the native enzyme forms were 33,200 (gel electrophoresis) and 38,200 +/- 5000 (gel filtration). This indicates that they are monomeric proteins sharing the same protein molecule. 3. AcPase III and IV differ essentially in thermostability and the activating effect of ConA binding. 4. AcPase III and IV are considerably activated with DTT but they differed markedly by the extent of this activation and the accompanying changes of their pH-activity curves. 5. It is suggested that the frog liver LMW AcPase represents a set of glycoforms whose different bioactivity is determined by the redox states of their essential cysteine residues.

Acid Phosphatase↗
PubMed1988

The high molecular weight and the low molecular weight acid phosphatases of the frog liver and their phosphotyrosine activity.

1. Two molecular weight classes of non-specific acid phosphatases (AcPases) (3.1.3.2) are present in the frog (Rana esculenta) liver: a higher molecular weight (HMW) of Mr 140,560 and a lower molecular weight (LMW) of Mr 38,180 enzyme. 2. The LMW AcPase was described earlier and the HMW AcPase of optimum pH 4.8 is shown to be a L(+)-tartrate sensitive, thermolabile, dimeric glycoenzyme slightly activated by DTT. 3. The HMW and the LMW AcPases exhibit activity for phosphotyrosine which showed similar sensitivity to various effectors as the p-nitrophenyl phosphatase activity; however, both enzymes differed substantially in this respect suggesting that they might be involved in different metabolic steps.

Acid Phosphatase↗
PubMed1986

Catfish liver acid phosphatases: differently glycosylated enzyme molecules with altered kinetic properties.

Two forms of catfish liver acid phosphatase (AcPase I and II) were separated and purified to homogeneity and their carbohydrate compositions and some biochemical properties were studied. Evidence is given that AcPase I and II are differently glycosylated forms of the same enzyme. The enzyme forms differ significantly in the size and the composition of their carbohydrate components, sensitivity towards sulfhydryl-blocking and protecting reagents, sensitivity to ferric and ferrous ions, thermostability and ability to hydrolyze some nucleotides. The more highly glycosylated form is more sensitive to thermal denaturation. AcPase I and II behave differently towards ascorbate and changes in its concentration and it is suggested that the concentration of reducing modifiers may regulate AcPase activity at the cellular level. It is hypothesized that the differing extents of glycosylation influence the structure of the enzyme forms. This is expressed in altered conformations of two enzyme forms and results in a different exposure of the essential cysteine residues.

Acid Phosphatase↗
PubMed1985

Studies of the heterogeneity of carp liver acid phosphatases: acid phosphatase--I. Subunit structure and carbohydrate composition.

The three molecular forms of the carp liver acid phosphatase (AcPase) were shown to be dimeric proteins, two of them differing in molecular weights. An activating effect of ConA binding on the AcPases has been observed. AcPase I and AcPase II showed a mol. wt of 122,500 and of 58,884 +/- 3000 for their subunits. It is assumed that AcPase I is a sialylated derivative of AcPase II. AcPase III has a mol. wt of 93,132 and the two subunits of 46,556 +/- 4000. A homogeneous AcPase I was obtained and its carbohydrate composition is presented.

Acid Phosphatase↗
PubMed1985

Isolation and characterization of a homogeneous acid phosphatase from catfish liver.

A homogeneous, tartrate-inhibitable acid phosphatase (AcPase) was obtained from the liver of channel catfish (Ictalurus punctatus) by the use of Affi Gel-10-coupled aminohexyltartramic acid affinity chromatography. The enzyme has a molecular weight of 82,500 and is a dimer consisting of two apparently equivalent subunits with subunit weights of 35,000 +/- 3000. Amino acid composition data are presented and compared with those of mammalian acid phosphatases. Data suggest that the enzyme is a metalloacid phosphatase. Catfish liver AcPase exhibits two molecular forms with pI 5.66 and 5.37 which were separated by chromatofocusing. A spontaneous conversion of the less acidic form to a more acidic form was observed and this conversion was accompanied by a decreased sensitivity towards tartrate inhibition.

Acid Phosphatase↗