Heat-stable Fraction Research Articles

Subcellular Distribution of Cadmium and Nickel in Chronically Exposed Wild Fish: Inferences Regarding Metal Detoxification Strategies and Implications for Setting Water Quality Guidelines for Dissolved Metals

ABSTRACT The objective of this study was to investigate metal detoxification in chronically exposed juvenile yellow perch (YP: Perca flavescens) and to field test the commonly assumed threshold toxicity model. Fish were collected from lakes located along a cadmium (Cd) and nickel (Ni) concentration gradient. Ambient dissolved metal concentrations were measured to evaluate exposure and total hepatic metal concentrations were determined as a measure of metal bioaccumulation. Hepatic metal partitioning among potentially metal-sensitive fractions (heat-denatured proteins, organelles) and detoxified metal fractions (metallothionein) was determined after differential centrifugation of YP liver homogenates. Major proportions of hepatic Cd were found in the heat-stable cytosolic peptides and proteins fraction (HSP; including metallothioneins), whereas Ni was mainly found in the potentially metal-sensitive heat-denaturable proteins fraction (HDP). For these chronically exposed fish there was no threshold exposure concentration below which binding of Cd or Ni to the heat-denaturable protein fraction or the organelle fraction did not occur. Metal detoxification was clearly incomplete and P. flavescens was subject to some metal-related stress, as evidenced notably by endocrine perturbations. Similar subcellular partitioning results were obtained when juvenile yellow perch were transferred from a reference lake to a Cd-contaminated lake and Cd accumulation was followed over time; there was no accumulation threshold below which Cd binding to the putative metal-sensitive fractions (HDP and organelles) did not occur. The presence of Cd and Ni in these fractions, even for low exposure concentrations and low hepatic accumulation, contradicts the threshold toxicity model that underpins metal toxicology theory and that is implicitly used in setting water quality guidelines for metals. Chronically exposed YP appear to have settled for a tradeoff between the cost of turning on their detoxification apparatus at full capacity, to completely suppress metal binding to metal-sensitive sites, and the alternative cost of allowing some binding of inappropriate metals to metal-sensitive sites.

Inactivation kinetics of pectin methyl esterase under combined thermal–high pressure treatment in an orange juice–milk beverage

The inactivation kinetics of PME in an orange juice–milk beverage system treated by thermal (65–80 °C) and combined thermal (25–65 °C)–high pressure (0.1–700 MPa) processes were fitted using a biphasic model. About 6–8% of the initial activity corresponding to the heat and pressure stable fraction was observed. For complete inactivation a treatment at 90 °C, 1 min or 700 MPa at 55 °C for 2 min was necessary showing the protective effect of the orange–milk media. The extent of inactivation was different in the orange matrices showing that PME was more thermostable in the orange juice–milk based beverage system as compared to the purified enzyme in a buffer system. On the other hand, the purified enzyme in a buffer system showed the highest pressure stability. Parameters such as pH (from acid in the orange juice matrices to basic in the buffer), matrix composition (from less to more complex) and purification level of the enzyme (purified in the buffer or nature in the orange juice) play an important role in the stability of the PME against the different processing technologies studied.

Role of heat stable fraction of alkaline phosphatase as an adjunct to ca 125 in monitoring patients of epithelial ovarian carcinoma

Heat stable fraction (HSF) of alkaline phosphatase (ALP) was evaluated as an adjunct to CA 125 as a tumour marker for epithelial ovarian cancer in a follow-up study. In our study group 63.4% of patients had elevated HSF levels (≥10U/L) and 93.3% had elevated CA 125 levels (>35U/mL). The sensitivity of CA 125 and HSF was 93.3% and 63.3% respectively. The decline in the activity of HSF, over the pre-op levels was highly significant after the first (p=0.001) chemotherapy cycle and significant after the second and third cycles (p<0.029). Thereafter, HSF activity was almost undetectable. The decrease in CA 125 levels over the pre-op levels was significant after the first, second, third (p<0.001) and fourth (p<0.034) chemotherapy cycle. HSF can be used alone or as an adjunct to CA 125 in screening and monitoring patients of ovarian carcinoma especially in remote areas where sophisticated facilities are not available and in patients in which CA 125 levels are not raised preoperatively.

Association of metals (mercury, cadmium and zinc) with metallothionein-like proteins in storage organs of stranded dolphins from the Mediterranean sea (Southern Italy).

Selected toxic and essential metals (mercury, Hg; cadmium, Cd; and zinc, Zn) were determined in the liver and in the kidney collected from 13 dolphins (Stenella coeruleoalba and Tursiops truncatus) stranded along the southern coasts of Italy from 1991 to 1999. Liver samples were also analysed for their methyl mercury (MeHg) and selenium (Se) contents. For subcellular fractionation, liver and kidney samples were homogenized in Tris-HCl buffer; after centrifugation, the supernatant (cytosol) was separated from pellets (insoluble fraction), heated at 80 degrees C for 10 min and centrifuged in order to separate the precipitate containing the thermolabile high molecular weight proteins. The cytosol heat-stable fraction, including metallothionein-like proteins (MTLPs), was then purified by gel filtration chromatography on Sephadex G-75 column. The three subcellular fractions collected (insoluble fraction, thermolabile fraction and purified heat-stable fraction) were analysed for their Hg, Cd and Zn contents. The analytical results confirm previous similar studies on toothed whales in showing that: (1) in the liver, as well as in the kidney, Hg was mainly found in the insoluble fraction, therefore, metallothioneins seem to have no role in the Hg detoxification; (2) in the liver, the molar ratio between Se and inorganic Hg was very close to 1; this suggests that the final compound of MeHg detoxification could be HgSe (tiemannite); (3) in almost all the samples, Cd and Zn were detected in the purified heat-stable fraction (including MTLPs). The mechanism of Cd detoxification and Zn homeostasis is also discussed.

Discovery of DNA Polymerase

Discovery of DNA Polymerase

Influence of sugars and polyols on the thermal stability of purified tomato and cucumber pectinmethylesterases: a basis for TTI development

Tomato and cucumber pectinmethylesterases (PME) were extracted and purified by affinity chromatography using kiwi PME inhibitor (PMEI) as a ligand. The optimal pH ionic strength combination, which led to a maximal thermostability of purified cucumber PME was identified as 6.7 and 1.25 M NaCl, respectively. The effect of sugars such as sucrose and trehalose and the effect of polyols including mannitol, sorbitol, lactitol and glycerol on the thermostability of purified PME was evaluated based on the residual enzymic activity after isothermal treatments performed in temperatures between 55 and 77 °C. Under all conditions, purified tomato PME showed a first order inactivation curve, while purified cucumber PME showed a biphasic inactivation curve. Purified tomato PME showed a maximal thermostability in citrate buffer, pH 4.5 complemented with glycerol 50% (v/v) ( D 77 °C -value of 6.62 min and z-value of 5.34 °C). The heat stable fraction of purified cucumber PME exhibited a maximal thermostability in Bis–Tris buffer, pH 6.7, 1.25 M NaCl complemented with glycerol 60% (v/v) ( D 75 °C -value of 2.79 min and z-value of 5.23 °C). The potential of both PME to be used as time–temperature integrators (TTIs) to monitor pasteurization process is discussed. Finally, when calculating the equivalent number of hydroxyl groups ( nOH) provided by each stabilizer per volume unit of enzyme solution, it could be observed that the D-value for purified tomato PME was exponentially related to the nOH. This observation may be used as a predictive tool for enzyme stabilization. The influence of the OH source on the thermal stability was also investigated in terms of nature of the OH source (nature of the molecule and level of polymerization of a polyvinyl alcohol, PVA).

Sub-cellular partitioning of essential and non-essential metals in a freshwater mollusc,Pyganodon grandis, collected in the field along a polymetallic environmental gradient

The cellular alterations normally induced by metals at high concentrations can be prevented by detoxification processes [1] such as sequestration into cellular compartments (calcium concretions, lysosoiues, etc.) or their binding to specific cellular ligands like metallothionein [2]. The aim of this project was to study and compare the subcellular partitioning of three metals (Cd. Cu, Zn) in gills of a freshwater molluse, Pyganodon grandis, collected along a polymetallic environmental gradient (nine lakes in the Rouyn-Noranda area, Abitibi, QC, Canada). Differential centrifugation was used to partition metals among different subcellular fractions. In the gills, along the environmental metal gradient, total tissue metal concentrations were positively correlated with concentrations in the granule traction; gill tissues contained high amounts of calcium concretions, which acted as preferential sites for sequestration of the three metals. An increase in Cd concentration was observed in the heat stable proteins fraction (including metallothionein), but not in the heat-denatured proteins fraction, suggesting that Cd-induced cell injury could be prevented by the involvement of maltiple cellular compartments in a protective role.

Expression of an ABA responsive 21 kDa protein in finger millet ( Eleusine coracana Gaertn.) under stress and its relevance in stress tolerance

Stress responsive genes are expressed in response to mild non-lethal induction stress. An optimum induction protocol for salinity stress was developed for finger millet seedlings. Seedlings induced with 200 mM NaCl showed substantially high recovery growth compared to non-induced seedlings. The addition of ABA during induction markedly increased recovery growth when challenged with a very high concentration of NaCl (up to 600 mM). A number of stress responsive proteins were expressed upon induction. Among them, 21 kDa protein was the most prominent. 35S methionine incorporation studies showed that >60% of the total label in the heat stable protein fraction was in the 21 kDa protein. The expression of this protein was seen within 2 h of induction stress. Further, the 21 kDa protein is induced under desiccation, low temperature, ABA and ABA together with NaCl, indicating that it is ABA responsive. This protein showed considerable accumulation in the mature seed and exhibited a strong cross-reaction with the antibodies raised against the conserved sequence of LEA 1 group of proteins, suggesting that the 21 kDa protein belongs to LEA 1. The relevance of this protein was examined in species varying in stress tolerance (finger millet, setaria, proso millet and cucumber). Cucumber, a salinity sensitive species, did not show any detectable level of expression of this protein. The relatively tolerant species, such as finger millet and proso millet, showed higher levels of expression compared to setaria, which is a sensitive species, signifying the relevance of the 21 kDa protein in stress tolerance.

Analysis of the effects of heat treatment on gliadin immunochemical quantification using a panel of anti-prolamin antibodies.

Antigen-labeled capture enzyme-linked immunosorbent assay with four different anti-gliadin monoclonal antibodies and an anti-gliadin serum and two different sample systems (purified gliadin fractions heat-treated in soluble phase and a model of dough simulating a baking process) were employed to study the effects of heat treatment on gliadin quantification. The analysis of purified gliadins showed that there is no particularly heat stable fraction. Remarkably, omega-gliadin did not present a differential heat stability. Reactivity varied depending on the time-temperature conditions of the treatment, the antibody employed, and the fraction analyzed. Heated dough samples showed an impairment of protein extraction depending on the intensity of the treatment. Capillary electrophoresis analysis of extracts showed that each gliadin group is affected to a different extent; omega-gliadin is less modified. Immunochemical analysis of the heat-treated samples using either of the five antibodies showed a decrease in the quantified gliadin, in concordance to the loss in the extracted proteins. Among the different sources of error in gliadin immunochemical quantification, the impairment in extraction efficiency in heat-treated samples appears as a major drawback to be overcome.

Determination of Cadmium Partitioning in Microalgae and Oysters: Contribution to the Assessment of Trophic Transfer

Alternative methodologies have been applied to the study of cadmium transfer in a food chain: water, microalgae (Skeletonema costatum and Tetraselmis suecica), oysters (Crassostrea gigas). The potential bioavailability of Cd in organisms was assessed through partitioning at the cell or tissue levels, and the predictive value of this method was evaluated by determining directly the metal transfer in an experimental food chain model. Cd concentrations were lower in S. costatum than T. suecica, in controls as well as in contaminated algae. In both algal species, Cd was firmly bound to the cell wall or had entered the cell. Cytosolic Cd was bound to intracellular ligands, the biochemical characteristics of which were not consistent with the hypothesis of detoxification via phytochelatins. In both algal species, Cd was predominantly present in the insoluble fraction, but at pHs such as those existing in the digestive tract of bivalves, it was easily extracted from the cells. Thus, exposure to Cd through phytoplanktonic food induced a significant uptake of this metal in soft tissues of bivalves. Due to the difference in Cd accumulation in algae, Cd doses associated with S. costatum were lower than those bound to T. suecica. Moreover, oysters retained a lower percentage of the metal associated with S. costatum compared to T. suecica (9 and 20%, respectively, after 21 days of exposure). Cd doses potentially available to oysters exposed directly in sea water were considerably higher, and direct uptake induced the highest levels of Cd incorporation but only 2% of dissolved Cd was actually retained by oysters over 21 days of exposure. In the soft tissues of oysters, Cd was distributed equally between soluble and insoluble fractions. Cytosolic Cd was present predominantly in the heat-stable fraction and mainly bound to compounds of molecular weight equal to 13.5 kDa. Moreover, a positive correlation was observed between metallothionein-like protein (MTLP) levels and gross concentrations of Cd in the soft tissues of oysters. These data are consistent with the hypothesis of an important role of metallothioneins in Cd metabolism in oysters and suggest a potential availability of MT-bound fraction of Cd to the consumers. These data are in agreement with the response of oysters exposed to Cd in the field.

The potential use of metallothionein in the clam Ruditapes decussatus as a biomarker of in situ metal exposure.

This work aimed to validate the relationship between metallothioneins (MTs) and metals (Cd, Cu and Zn) in field conditions. Specimens of the marine bivalve Ruditapes decussatus (Linné, 1758) from Gargour were transferred in two sites: Gargour and Sidi Mansour, both situated along the south-eastern coast of Tunisia. The bivalves were removed from pairs of cages at day 0 (date of transplantation), day 62 and day 132. Metals (Cd, Cu and Zn) and MTs were determined in the subcellular fractions of the digestive gland. In Gargour, metal and MT levels increased significantly after 62 days of transplantation. However, they showed modest and non-significant variations in Sidi Mansour. Zn was mainly associated with the insoluble fraction, whereas Cd and Cu percentages in the soluble and the insoluble fractions were equivalent. Simple correlation analysis showed a positive and significant relationship between MTs and each metal. If all metals were taken together, multiple correlations showed that MTs were significantly correlated with Cd and Zn, with an important coefficient for Cd, but no significant relationship was observed for Cu. Gel filtration chromatography showed that in the heat stable fraction, the only cytosolic SH rich compounds have an apparent low molecular mass (about 15 kDa), which could correspond to metallothioneins. In the digestive gland of R. decussatus MTs responded to moderate increases of metal contamination, without interference with other factors, and could be a promising biochemical indicator of metal exposure.

Molecular Characterization Reveals Identity of Microtubule-Associated Proteins MAP3 and MAP4

The identity of two microtubule-associated proteins, MAP3 and MAP4, was verified both immunologically and biochemically. MAP3 was enriched from the heat-stable fraction of rat brain extracts by reverse-phase HPLC and preparative two-dimensional gel electrophoresis. Both MAP3 and MAP4 antibodies reacted with the corresponding spots on two-dimensional Western blots. Amino acid sequences of internal peptides derived from rat MAP3 matched with corresponding sequence stretches of mouse MAP4. In the kidney cortex, the MAP3 antibody stained not only glomerular podocytes but also interstitial cells. This distribution pattern of MAP3 is identical to that of MAP4 reported previously. These results indicate that MAP3 and MAP4 are identical.

Separation and thermal characterization of ionically and tightly cell-wall-bound pectin methylesterase from cucumbers ( Cucumis sativus )

Thermal characteristics of cell-wall-bound pectin methylesterase (PME) from cucumbers were determined. Heat inactivation of PME followed first-order reaction kinetics. Biphasic inactivation curves indicated the presence of heat-labile and heat-stable fractions. Inactivation of PME accelerated above 65 °C. The z values between 70 °C and 80 °C were 7.6 °C and 9.0 °C for heat-stable fractions of ionically (IPME) and tightly cell wall bound PME (TPME), respectively. Temperature optima for the initial activities of IPME and TPME were 65 °C and 60 °C, respectively. However, for longer periods of activity determination, both IPME and TPME showed a temperature optimum at 50 °C. The Ea values for initial activities were 5 kcal mol–1 (20–65 °C) and 7.2 kcal mol–1 (20–60 °C) for IPME and TPME, respectively.

Single, combined, or sequential action of pressure and temperature on lipoxygenase in green beans (Phaseolus vulgaris L.): a kinetic inactivation study.

The objective of this investigation was to study kinetically the effect of pressure and temperature either as a single, as a combined, or as a sequential action on lipoxygenase (LOX) inactivation in crude green beans extract. The LOX isozymes in green beans extract had a different heat sensitivity but a similar pressure stability: two fractions following apparent first-order reactions, i.e., a heat-labile fraction and a heat-stable fraction, were observed in studies on its thermostability, whereas only one fraction following a first-order reaction was noticed in studies on its pressure stability. At ambient pressure, irreversible LOX inactivation was studied in a temperature range from 55 to 70 degrees C. At room temperature, pressures around 500 MPa were required in order to inactivate LOX in green beans extract. The effect of a pressure or a thermal pretreatment on LOX thermo- or barostability, respectively, was also investigated but no significant differences in inactivation kinetics due to the pretreatment were observed.

Partial Purification and Thermal Characterization of Peroxidase from Okra (Hibiscus esculentum)

Thermal characteristics and substrate specificity of peroxidase (POX) from okra were determined. Crude POX was separated into eight fractions (P1−P8) by DEAE−cellulose chromatography. Heat inactivation of POX was biphasic and fitted to a first-order kinetic model. Inactivation rates of crude POX and eight POX fractions at 70 °C varied between (63.499 and 123.809) × 10-2 min-1 for the heat-labile fractions and (11.255 and 31.441) × 10-2 min-1 for the heat-stable fractions. Activation energies for the inactivation of crude extract were 37.0 kcal mol-1 with a z-value of 13.8 °C for the heat-labile fraction and 37.8 kcal mol-1 with a z-value of 13.5 °C for the heat-stable fraction. Optimum temperatures were between 30 and 35 °C for the crude extract, 60 °C for P1−P5 fractions, and more than 65 °C for P6−P8 fractions. Among substrates, guaiacol was oxidized primarily by P1−P6 fractions; whereas, pyrogallol and catechin were preferred by P7 and P8, respectively. Keywords: Peroxidase; okra; partial purification; thermal characterization; substrate specificity

Second trimester calcium-phosphorus-magnesium homeostasis in women with threatened preterm delivery.

The effect of threatened preterm delivery on calcium, phosphorus, magnesium homeostasis in the second trimester of pregnancy was investigated. Serum concentrations of total and ionized calcium, inorganic phosphorus, magnesium, total protein, albumin, total estrogens and human placental lactogen were determined in women with threatened preterm delivery at 23-28 weeks of gestation (the studied group) and in women with uncomplicated pregnancy of the same duration (the control group). Additionally activities of total alkaline phosphatase and heat-stable alkaline phosphatase fraction were measured. Patients of the studied group compared to the control group showed decreased concentration of total calcium (2.15 +/- 0.073 vs. 2.25 +/- 0.11 mmol/l, P < 0.001), inorganic phosphorus (1.21 +/- 0.26 vs. 1.34 +/- 0.22 mmol/l, P < 0.01) and magnesium (0.63 +/- 0.053 vs. 0.71 +/- 0.12 mmol/l, P < 0.001), total protein (64.0 +/- 5.4 vs. 68.6 + 1.0 g/l, P < 0.001), albumin (546.3 +/- 55.1 vs. 579.6 +/- 49.3 micromol/l, P < 0.003) and placental lactogen (3664 +/- 1806 vs. 4651 +/- 1858 ng/ml, P < 0.02); they also demonstrated decreased activity of total alkaline phosphatase (42.17 +/- 16.99 vs. 50.66 +/- 6.56 IU/l, P < 0.001) and its heat stable fraction (22.65 +/- 7.89 vs. 31.89 +/- 9.09 IU/l, P < 0.001). Patients of the studied group showed normal values of ionized calcium and total estrogens. Premature uterine contractility in women in the second trimester is accompanied by lowered serum concentrations of total calcium, inorganic phosphorus, magnesium, total protein and albumin. There is also decreased activity of total alkaline phosphatase, its heat-stable fraction and placental lactogen which may have diagnostic value. Premature uterine contractility in women in the second trimester may be related to the disturbances of calcium-phosphorus-magnesium homeostasis and calcium supplementation should be considered.

Human placental extract stimulates liver regeneration in rats.

The effect of human placental extract (HPE) on liver regeneration in rats was investigated. After intravenous administration of HPE to a-naphthylisothiocyanate (ANIT)-intoxicated rats, the labeling index in hepatocytes was significantly increased to a level 16.5 times higher than that of the control. A 1/500 dilution of HPE directly stimulated DNA synthesis of the hepatocytes in primary culture. HPE heated at 121 degrees C did not stimulate the labeling index in vivo or hepatocyte DNA synthesis in primary culture, suggesting that HPE contains heat-unstable but potent mitogens for hepatocytes. HPE contains hepatocyte growth factor (HGF), but the mitogenic effect of HPE cannot be explained by the effect exerted by HGF alone, since both the labeling index in vivo and hepatocellular DNA synthesis in vitro stimulated by HPE were much higher than those stimulated by HGF alone when the applied doses of HGF were set to be almost the same level between each case. When HPE was fractionated on a heparin-sepharose column, the mitogenic effect of HPE was found to be located mainly in the heparin-bound fraction. Hepatocyte DNA synthesis induced by this fraction was enhanced cooperatively by the heparin-unbound fraction, suggesting that there are some modulators in the heparin-unbound fraction which enhance the proliferative activity of the heparin-bound fraction by a synergetic mechanism. Both HPE and heated HPE completely recovered the biochemical marker activity for liver function (glutamic-pyruvic transaminase, GPT; alkaline phosphatase, ALP; lactate dehydrogenase, LAP; gamma-glutamyltransferase, gamma-GTP activities and the bilirubin concentration) almost to the control level in the serum of ANIT-intoxicated rats, indicating that HPE also contains a heat-stable fraction which repairs liver function.

Stabilization of phospholipase C fromClostridium perfringens by conjugation with a trypsin inhibitor

A new approach for the stabilization of phospholipase C by conjugation with a proteinase inhibitor is proposed. A heat-stable fraction obtained from a conjugate retained its initial activity for an hour at an incubation temperature of 50°C. An appropriate method of conjugation using an affinity adsorbent preventing the appearance of inactive forms of the conjugate has been developed.

Characterization of a heat-stable fraction of lipovitellin and development of an immunoassay for vitellogenin and yolk protein in winter flounder (Pleuronectes americanus).

An enzyme-linked immunoabsorbent assay was developed for detection and quantification of the yolk protein lipovitellin (Lv) and its plasma precursor, vitellogenin (Vg), in winter flounder (Pleuronectes americanus). Native Lv was found to be a mixture of heat-stable and heat-labile molecules in mature, ovulated eggs. A heat-stable Lv fraction was purified from extracts of unfertilized eggs by brief heat treatment and gel permeation chromatography on Bio-Gel A-1.5. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of heat-stable Lv revealed a single polypeptide of 94 kD, while native Lv also possessed several smaller polypeptides, suggesting that heat-labile Lv contains proteolytic cleavages of the 94-kD polypeptide which destabilize its structure. The Stokes radius of the native protein on Bio-Gel A-1.5 was estimated at 4.50 nm, while the Stokes radii of heat-stable and heat-labile Lv were 4.26 nm and 5.17 nm, respectively. Heat-stable Lv was used to produce a rabbit polyclonal antiserum which reacted with a single 175-kD polypeptide in Western blots of vitellogenic female winter flounder serum, but did not react with any component of male serum. Ouchterlony double diffusion using this antiserum demonstrated immunological identity of Lv, heat-stable Lv, and Vg. The anti-Lv anti-serum was used to construct an homologous ELISA with a linear response between 25 and 300 ng/ml. This assay was used to characterize a Bio-Gel A-1.5 column profile of serum from an estradiol-treated male winter flounder, and a single peak, with Stokes radius of 6.70 nm, was identified as Vg. Winter flounder Vg was confirmed to be a dimer, while Lv from mature eggs was found to be a monomer of a lower molecular weight polypeptide.

Calcium-phosphorus-magnesium homeostasis in women with threatened preterm delivery

Objective: The effect of threatened preterm delivery on calcium, phosphorus, magnesium homeostasis in the third trimester of pregnancy was investigated. Methods: Serum concentrations of total and ionized calcium, inorganic phosphorus, magnesium, total protein, albumin, total estrogens and human placental lactogen were determined in women with threatened preterm delivery at 29–36 weeks of gestation (the studied group) and in women with uncomplicated pregnancy of the same duration (the control group). Additionally, activities of total alkaline phosphatase and heat-stable alkaline phosphatase fraction were measured. Results: Patients of the studied group compared to the control group showed decreased concentration of total calcium (2.17 ± 0.09 vs. 2.28 ± 0.13 mmol/l, P < 0.0005), inorganic phosphorus (1.13 ± 0.27 vs. 1.32 ± 0.23 mmol/l, P < 0.001) and magnesium (0.64 ± 0.07 vs. 0.70 ± 0.10 mmol/l, P < 0.003); they also demonstrated decreased activity of total alkaline phosphatase (70.8 ± 23.2 vs. 81.9 ± 14.9 IU/l, P < 0.01) and its heat-stable fraction (30.2 ± 15.6 vs. 59.6 ± 14.9 IU/l, P < 0.001). In the studied group no difference was found in concentrations of investigated ions and enzymes between women who delivered at term and women who delivered prematurely. Patients with threatened preterm delivery showed serum deficiency of total calcium, phosphorus and magnesium which might be related to premature uterine contractility but does not predict premature labor by week 36 of gestation (66% of patients delivered at term). Conclusion: The deficiency of minerals and lowered activity of total alkaline phosphatase is observed in women with threatened preterm delivery. Laboratory tests of calcium-phosphorus-magnesium homeostatsis have limited predictive value in regard to the term of delivery in women with threatened preterm delivery.