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PubMed2004

[Utilization of powdered peanut hull as biosorbent for removal of anionic dyes from aqueous solution].

An untried, low cost, locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated. Powder prepared from peanut hull had been used for biosorption of three anionic dyes, amaranth (Am), sunset yellow (SY) and fast green FCF (FG). The effects of various experimental parameters (e.g. initial pH and dye concentration, sorbent dosage, particle size, ion strength, contact time etc.) were examined and optimal experimental conditions were decided. At initial pH 2.0, three dyes studied could be removed effectively. When the dye concentration was 50 mg x L(-1), the percentages of dyes sorbed was 95.5% in Am, 91.3% in SY and 94.98% in FG, respectively. The ratios of dyes sorbed had neared maximum values in all three dyes when sorbent dose of 5.0 g x L(-1) and the sorbent particle size in 80-100 mesh was used. The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes. The equilibrium values arrived at about 36 hour for all three dyes. The isothermal data of biosorption followed the Langmuir and Freundlich models. The biosorption processes conformed the pseudo-first-order rate kinetics. The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater.

Adsorption↗
PubMed2002

Sensorimotor system measurement techniques.

OBJECTIVE: To provide an overview of currently available sensorimotor assessment techniques. DATA SOURCES: We drew information from an extensive review of the scientific literature conducted in the areas of proprioception, neuromuscular control, and motor control measurement. Literature searches were conducted using MEDLINE for the years 1965 to 1999 with the key words proprioception, somatosensory evoked potentials, nerve conduction testing, electromyography, muscle dynamometry, isometric, isokinetic, kinetic, kinematic, posture, equilibrium, balance, stiffness, neuromuscular, sensorimotor, and measurement. Additional sources were collected using the reference lists of identified articles. DATA SYNTHESIS: Sensorimotor measurement techniques are discussed with reference to the underlying physiologic mechanisms, influential factors and locations of the variable within the system, clinical research questions, limitations of the measurement technique, and directions for future research. CONCLUSIONS/RECOMMENDATIONS: The complex interactions and relationships among the individual components of the sensorimotor system make measuring and analyzing specific characteristics and functions difficult. Additionally, the specific assessment techniques used to measure a variable can influence attained results. Optimizing the application of sensorimotor research to clinical settings can, therefore, be best accomplished through the use of common nomenclature to describe underlying physiologic mechanisms and specific measurement techniques.

Journal Article↗
PubMed1997

Intestinal calcium absorption from mineral water.

Little is known about the bioavailability of calcium in water and various beverages. Some mineral waters contain large amounts of calcium that could compensate for insufficient consumption of dairy products. The fractional intestinal absorption of calcium (FCA) was measured in 12 healthy adult volunteers, using a trace dose of radiocalcium and 200 mg of calcium carrier, part of which was calcium contained in mineral water. Measurements were performed in fasting subjects consuming a standard breakfast. In all the subjects, three mineral waters with a calcium concentration of 10.4, 78, and 467 mg/l, respectively, were tested. Calcium absorption occurred with the same kinetics for each of the mineral waters tested, and within 2 h of the oral dose, equilibrium was reached between absorbed calcium and calcium remaining in the gastrointestinal tract, which resulted in a constant FCA value. This level comprising between 34.1 and 37.0% was independent of the daily calcium consumption and the chemical content of the mineral water. In conclusion, calcium contained in mineral waters in available for intestinal absorption. In a given normal subject, the only rate-limiting factor for FCA is the amount of total calcium given with foods and drinks. Mineral waters containing calcium are recommended as a supplemental source of calcium to achieve optimal calcium requirements, especially in aged people with lactose intolerance.

Adult↗
PubMed2005

Correlation energy functionals dependent on an effective number of electrons: charged species and equilibrium geometries.

Recently proposed spin-dependent and spin-independent correlation energy functionals [Perez-Jimenez et al., J. Chem. Phys. 116, 10571 (2002)] based on an effective number of electrons N are extended to deal with charged systems. By introducing the concept of an effective atomic number Z analogous to N, the spin-dependent functional in combination with Becke's exchange [Becke, Phys. Rev. A 38, 3098 (1988)] yields a mean absolute error (MAE) of 5.4 kcal/mol for the 88 ionization potentials and 58 electron affinities included in the extended G2 set, and a MAE of 4.1 kcal/mol for the 312 data comprising the above plus the 148 enthalpies of formation of the extended G2 set and the 18 total energies of the neutral atoms H through Ar. Geometry optimizations performed on the 53 molecules of the G2-1 test set with the above combination of exchange and correlation functionals yield MAEs of 0.017 A and 1.5 degrees for the 68 bond lengths and 29 angles analyzed as compared with the experimental estimates.

Journal Article↗
PubMed2006

Molecular vibrational analysis and MAS-NMR spectroscopy study of epilepsy drugs encapsulated in TiO2-sol-gel reservoirs.

A nanostructured matrix, consisting of titania, was designed in such a way that an antiepileptic drug could be encapsulated and released according to a well-defined time release schedule. The titania was synthesized by a sol-gel method in which titanium n-butoxide was used as the precursor for the formation of the sol. The synthesis was optimized to yield a homogeneous particle size with a high porosity and an anatase crystal structure. The antiepilectic drugs, phenytoine or valproic acid, were added during the gelation stage in order to obtain a homogeneous gel phase. The resulting nanostructured matrix including the drug showed only weak attractive forces, such as London forces, dipole-dipole coupling, and in some cases hydrogen bonds. The resulting assembly, referred to as a reservoir, was characterized using conventional FTIR and NMR spectroscopic techniques. Theoretical simulation studies were performed so as to obtain an understanding of the equilibrium electrostatic potential distribution and the relative charges on the titania and the anticonvulsants.

Anticonvulsants↗
PubMed1977

The effect of chelators on Mg2+, Na+-dependent phosphorylation of (Na+ + K+)-activated ATPase.

1. The effect of free Mg2+, MgEDTA and MgCDTA on the phofphorylation of the (Na+ + K+)-activated ATPase (ATP phosphohydrolase, EC 3.6.1.3) has been studied. 2. 10 mM trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA) added simultaneously with [gamma-32P]ATP to a solution containing the enzyme, 1 mM Mg2+ and 150 mM Na+ does not prevent formation of phospho-enzyme. When [gamma-32P]ATP is added after CDTA the level of phospho-enzyme obtained decreases with increase in the time interval between addition of CDTA and ATP. The inability of CDTA to prevent the formation of phospho-enzyme becomes more pronounced when the medium contains MgEDTA. In the presence of CDTA the maximum amount of phospho-enzyme formed increases with the MgEDTA concentration. 3. Without CDTA the steady-state level of phospho-enzyme is directly proportional to the logarithm of free Mg2+ concentration. Neither with suboptimal nor with optimal concentrations of free Mg2+ does MgEDTA have an effect on the level of phospho-enzyme formed. 4. Using the phospho-enzyme level as a measure of free Mg2+ the experiments show that CDTA reacts slower with Mg2+ than does EDTA, but the stability constant of MgCDTA complex is higher than of MgCDTA, complex. 5. Due to the higher stability constant, of MgCDTA, as compared to MgEDTA, addition of CDTA to a medium containing free Mg2+ and MgEDTA will not only chelate the free Mg2+, but it will also shift the equilibrium from MgEDTA towards MgCDTA, i.e. MgEDTA acts as a source of free Mg2+ which is then chelated by CDTA. The experiments show that it takes minutes before Mg2+, EDTA and CDTA come to equilibrium. Provided the dissociation of MgEDTA is faster than the formation of the MgCDTA complex, the medium will contain a concentration of free Mg2+ which at any given instant is near in equilibrium with a slowly decreasing concentration of MgEDTA; this free Mg2+ can support phosphorylation. This can explain why the rate with which CDTA stops phosphorylation decreases with an increase in the MgEDTA concentration. 6. When phosphorylation is stopped by addition of unlabelled ATP, the rate of dephosphorylation is faster than when it is stopped by addition of CDTA both with and without EDTA in the medium. CDTA reacts too slowly with Mg2+ to be used as a chelator in studies where a fast removal of Mg2+ is required. 7. A previous finding has been verified, namely that the rate of spontaneous, of K+-stimulated and of ADP-stimulated dephosphorylation is independent of the Mg2+ concentration during formation of phospho-enzyme.

Adenosine Triphosphatases↗
PubMed1996

Increased efficiency of alkaline phosphatase production levels in Escherichia coli using a degenerate PelB signal sequence.

To obtain an expression vector that will optimize secretion of proteins with disulfide bridges in Escherichia coli, we fused the phoA gene, encoding the bacterial alkaline phosphatase (PhoA), to the sequence encoding the pectate lyase B signal sequence (PelBSS). We used an extensively degenerate pelBSS with silent mutations to study their effects on the production level and activity of PhoA. 11 representative clones differed by a factor of five between the lowest and the highest level of activity, and by a factor greater than seven for the production levels. The efficiency of translocation seems to be the result of an equilibrium between production and secretion levels that favours the secretion of active PhoA according to the competence of the fusion protein being translocated. Free energy calculations and the predicted mRNA secondary structures of the translation initiation regions showed that the high stability of the secondary structure decreased production and secretion levels of PhoA and vice versa. A stem-loop encompassing the degenerate positions downstream from the AUG start codon appears to be responsible for the differences in the production levels.

Alkaline Phosphatase↗
PubMed1984

Chemical and statistical considerations in the determination of partition coefficients of weakly ionizable drugs and poisons.

Equations have been developed that relate the concentration (or a parameter directly proportional to concentration, such as optical absorbance) of a weakly ionizable solute in a water-immiscible phase, in equilibrium with an aqueous phase, to the pH of the aqueous phase, the partition coefficient of the unionized solute and the phase volume ratio. These relationships have been used in the design of experimental methods for determining partition coefficients, which require measurement of solute concentration in only one phase. Data obtained in this way permit ready recognition of deviations from assumptions made in the development of the model; these assumptions include insolubility of the ionized solute in the water-immiscible phase and lack of interaction between buffer components and solute. Conditions for optimal liquid-liquid extraction of weakly ionizable solutes are more easily recognized. With these techniques, the negative logarithm of the acid dissociation constant (pK'a) and the logarithm of the octanol-water partition coefficient (log P) have been measured for warfarin (pK'a = 5.15 +/- 0.04; log P = 2.82 +/- 0.06), strychnine (pK'a = 8.29 +/- 0.02; log P = 2.23 +/- 0.04), phenol (pK'a = 9.88 +/- 0.02; log P = 1.75 +/- 0.05), procaine (pK'a = 8.11 +/- 0.04; log P = 1.10 +/- 0.08), and ephedrine (pK'a = 9.92 +/- 0.01; log P = 1.65 +/- 0.04) at 21 degrees C.

Journal Article↗
PubMed1981

pH and temperature dependence of glutamine uptake, carbon dioxide and ammonia production in kidney slices from acidotic rats.

1. The effects of medium pH and temperature on glutamine uptake, NH3 production and CO2 production were examined using kidney cortex slices from normal and acidotic rats. 2. Uptake of glutamine by kidney slices from normal rats shows a pH optimum of 7.5 at 25 degrees C and 7.3 at 37 degrees C. Uptake is optimal, however, at a constant OH-/H+ ratio of 10. 3. In slices from acidotic rats greatest uptake was at pH 6.8 at 25 degrees C and 6.6 at 37 degrees C. Optimal OH-/H+ ratio was 0.4 and constant at both temperatures. 4. CO2 production from glutamine was greatest at pH 7.0 at 37 degrees C in slices from control rats. No pH optimum was detected at 25 degrees C. With slices from acidotic animals, optimal pH for CO2 production became identical with that for uptake. 5. Both basal and glutamine-stimulated NH3 production showed no optimal pH but were significantly higher in slices from acidotic rats compared with those from controls. 6. Dependence of glutamine penetration on optimal OH-/H+ ratio is considered to reflect a general membrane phenomenon which is produced by either an increase in carrier-substrate complexes or an increase in the number of carriers at this ratio. 7. Cellular penetration of glutamine does not appear to be a limiting factor in production of NH3 in vitro.

Acid-Base Equilibrium↗
PubMed1986

Multisubstrate analogs for deoxynucleoside kinases. Triphosphate end products and synthetic bisubstrate analogs exhibit identical modes of binding and are useful probes for distinguishing kinetic mechanisms.

Comparative inhibition kinetics with natural dNTP end products (dNp3) and new synthetic bisubstrate-type analogs, dNp4A (deoxynucleoside 5'-adenosine 5'''-P1,P4-tetraphosphate), have been studied with their target deoxynucleoside kinases from Lactobacillus acidophilus. Analysis of inhibition specificity, inhibition patterns, and Ki(app) under various conditions has revealed the following conclusions. Both dNTP and dNp4A bind to the active site of the corresponding kinase through multiple binding determinants. The deoxynucleoside moiety of dNTP fits optimally at the deoxynucleoside binding site and provides the basis for its inhibition specificity, whereas the triphosphate group interacts with the ATP binding site, reinforcing the affinity of the molecule as a potent end product inhibitor (Ki = 0.4-3 microM). The adenosine moiety of dNp4A does not contribute to the binding of this compound, whereas the tetraphosphate portion is the second binding determinant, just as in the model developed for dNTP. dNTP and dNp4A proved to be useful tools for distinguishing the kinetic mechanisms of kinases which follow sequential pathways, i.e. the rapid equilibrium Random Bi Bi for dCyd and dGuo kinases and the steady state Ordered Bi Bi mechanism for two dAdo kinases associated either with dCyd kinase or with dGuo kinase on different multifunctional proteins.

Adenosine Triphosphate↗
PubMedDate not supplied

[The interrelationship of changes in carbohydrate-energy metabolism and potassium homeostasis in children with diffuse suppurative peritonitis].

The parameters of potassium homeostasis (potassium concentration in the plasma, red cells, and urine and potassium to sodium ratio in the urine) and of carbohydrate-energy metabolism (CEM) assessed from the activities of the key enzymes of glycolysis and pentose phosphate route of glucose oxidation were determined in 52 patients on day 2 postoperation. Relationships between potassium metabolism and CEM status were revealed in children with diffuse peritonitis. Disorders in potassium homeostasis were associated with CEM changes. In children with a favorable course of the disease the adaptation changes in the metabolic system, characterized by increased intensity of glucose oxidation and intactness of cellular energy homeostasis, permit the maintenance of potassium homeostasis at optimal potassemia of low therapeutic value. In case of a lethal outcome failure of therapeutic measures aimed at correction of potassium homeostasis is coupled with CEM disorders manifesting by reduced glucose oxidation after the pentose phosphate route, reduced concentration of adenyl nucleotides, disordered membrane permeability, and accumulation of organic acids.

Acid-Base Equilibrium↗
PubMed1982

Dopamine receptors in rat brain regions. Optimal conditions for 3H-agonist binding, pH dependency and lack of inhibition by ascorbic acid.

The binding of dopaminergic agonist and antagonist radioligands was investigated in rat brain regions. A 30-min preincubation of homogenates of caudate nucleus or mesolimbic brain regions at 37 degrees induced a several-fold increase in the stereospecific binding of [3H]-dopamine or [3H]apomorphine to the subsequently washed particulate fraction, whereas it induced a slight decrease in [3H]spiroperidol binding. Stereospecific 3H-agonist binding was not observed in brain regions devoid of dopaminergic innervation. Guanosyl nucleotides, EDTA or ethyleneglycol-bis-(beta-amino-ethyl ether) N,N'-tetraacetate (EGTA), included in the preincubation buffer, antagonized the stimulation of 3H-agonist binding. The stereospecific binding sites of 3H-agonists were saturable with equilibrium dissociation constants (Kd) of 1-2 nM. High-affinity binding was pH dependent, with different pH optima for each radioligand. Several dopamine receptor agonists and antagonists were potent inhibitors of stereospecific [3H]dopamine binding, whereas l-ascorbic acid was inactive at concentrations as high as 1.0 mM. The stereospecific binding of [3H]apomorphine or [3H]spiroperidol was also unaffected by ascorbic acid. The nonspecific (d-butaclamol-insensitive) portion of 3H-agonist binding was weakly inhibited by concentrations of ascorbic acid higher than 0.01 mM. This effect was also observed in the cerebellum and spinal cord, where none of the 3H-agonist binding was stereospecific. It is concluded that the portion of 3H-agonist or 3H-antagonist radioligand binding which is related to dopamine receptors is unaffected by ascorbic acid.

Animals↗
PubMed1991

Steroid hormone receptors.

In the three decades since the original discovery of receptors for steroid hormones, much has been learned about the biochemical processes by which these regulatory agents exert their effects in target tissues. The intracellular receptor proteins are potential transcription factors, needed for optimal gene expression in hormone-dependent cells. They are present in an inactive form until association with the hormone converts them to a functional state that can react with target genes. Transformation of the receptor protein to the nuclear binding form appears to involve the removal of both macromolecular and micromolecular factors that act to keep the receptor form reacting with DNA. Much of the native receptor is present in the nucleus, loosely bound and readily extractable, but for some and possibly all steroid hormones, some receptor is in the cytoplasm, perhaps in equilibrium with a nuclear pool. Methods have been developed for the stabilization, purification, and characterization of receptor proteins, and through cloning and sequencing of their cDNAs, primary structures for these receptors are now known. This has led to the recognition of structural similarities among the family of receptors for the different steroid hormones and to the identification of regions in the protein molecule responsible for the various aspects of their function. Monoclonal antibodies recognizing specific molecular domains are available for most receptors. Despite the knowledge that has been acquired, many important questions remain unsolved. How does association with the steroid remove factors keeping the receptor protein in its native state, and how does binding of the transformed receptor to the response element in the promoter region enhance gene transcription? Once it has converted the receptor to the nuclear binding state, is there a further role for the steroid in modulating transcription? Still not entirely clear is the involvement of phosphorylation and/or dephosphorylation in hormone binding, receptor transformation, and transcriptional activation. Less vital to basic understanding but important in the overall picture is whether the native receptors for gonadal hormones are entirely confined to the nucleus or whether there is an intracellular distribution equilibrium. With the effort now being devoted to this field, and with the application of new experimental techniques, especially those of molecular biology, our understanding of receptor function is progressing rapidly. The precise mechanism of steroid hormone action should soon be completely established.

Amino Acid Sequence↗
PubMed2002

MR imaging of knee cartilage with FEMR.

OBJECTIVE: Fluctuating equilibrium magnetic resonance (FEMR) is a rapid three-dimensional (3D) imaging sequence with high signal-to-noise ratio (SNR). FEMR may be useful for detecting cartilage defects in the knee. At 1.5 T, FEMR uses a TR with odd multiples of 2.2 ms for fat/water separation. With a TR of 6.6 ms, high-resolution 3D imaging of cartilage is possible. DESIGN AND PATIENTS: The knees of 10 volunteers and two patients were imaged on a GE Signa 1.5 T scanner using an extremity coil. Scans were preceded by a shimming sequence optimizing linear terms. Subjects were imaged with FEMR, proton-density fast spin-echo (PD-FSE), T2-weighted fast spin-echo (T2-FSE), and 3D fat-suppressed spoiled-gradient-recalled echo (3D-SPGR). RESULTS: SNR and contrast-to-noise efficiency measurements for cartilage using FEMR were superior to those using PD-FSE, T2-FSE, and 3D-FS-SPGR. FSE images showed bright synovial fluid with limited cartilage detail. 3D-SPGR had comparable resolution to FEMR but suboptimal cartilage/fluid contrast and longer scan times (8 min versus 2 min). Cartilage surface detail, outlined by bright synovial fluid, was best seen on the FEMR images. DISCUSSION: FEMR obtains high-resolution 3D images of the entire knee in 2 min with excellent cartilage/fluid contrast. FEMR is sensitive to field inhomogeneity and requires shimming. Surface defects are outlined by bright synovial fluid, and cartilage has higher signal-to-noise efficiency compared with PD-FSE, T2-FSE, and 3D-SPGR techniques.

Cartilage, Articular↗
PubMed2005

Enantiomeric separation of gemfibrozil chiral analogues by capillary electrophoresis with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin as chiral selector.

The enantiomeric separation of gemfibrozil chiral analogues was performed by capillary zone electrophoresis (CZE). Resolution of the enantiomers was achieved using heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TM-beta-CD) as chiral selector dissolved into a buffer solution. In order to optimize the separation conditions, type, pH and concentration of running buffer and chiral selector concentration were varied. For each pH value, the optimum chiral selector concentration that produced the resolution of the isomers was found. The migration order of labile diastereoisomers formed was valued at the optimum experimental conditions by adding a pure optical isomer to the racemic mixture. Data from 1H NMR studies confirmed host-guest interaction between TM-beta-CD and 5-(2,5-dimethylphenoxy)-2-ethylpentanoic acid sodium salt. The hypothesized stoichiometry host:guest was 1:1. An apparent equilibrium constant (Ka) was estimated monitoring the chemical shift variation as a function of TM-beta-CD concentration. Salt effect on complexation equilibrium constant was also investigated.

Buffers↗
PubMed2004

Biosorption of nickel(II) and copper(II) ions from aqueous solution by Streptomyces coelicolor A3(2).

The biosorption of nickel(II) and copper(II) ions from aqueous solution by dried Streptomyces coelicolor A3(2) was studied as a function of concentration, pH and temperature. The optimum pH range for nickel and copper uptake was 8.0 and 5.0, respectively. At the optimal conditions, metal ion uptake was increased as the initial metal ion concentration increased up to 250 mg l(-1). At 250 mg l(-1) copper(II) ion uptake was 21.8% whereas nickel(II) ion uptake was found to be as high as 7.3% compared to those reported earlier in the literature. Metal ion uptake experiments were carried out at different temperatures where the best ion uptake was found to be at 25 degrees C. The characteristics of the adsorption process were investigated using Scatchard analysis at 25 degrees C. Scatchard analysis of the equilibrium binding data for metal ions on S. coelicolor A3(2) gave rise to a linear plot, indicating that the Langmuir model could be applied. However, for nickel(II) ion, divergence from the Scatchard plot was evident, consistent with the participation of secondary equilibrium effects in the adsorption process. Adsorption behaviour of nickel(II) and copper(II) ions on the S. coelicolor A3(2) can be expressed by both the Langmuir and Freundlich isotherms. The adsorption data with respect to both metals provide an excellent fit to the Freundlich isotherm. However, when the Langmuir isotherm model was applied to these data, a good fit was obtained for the copper adsorption only and not for nickel(II) ion.

Adsorption↗
PubMed2003

Characterization and optimization of a chromatographic process based on ethylenediamine-N,N,N',N'-tetra(methylphosphonic) acid-modified zirconia particles.

The primary objective of work was to characterize, optimize and model a chromatographic process based on ethylenediamine-N,N,N',N'-tetra(methylphosphonic) acid (EDTPA)-modified zirconia particles. Zirconia particles were produced by spray-drying colloidal zirconia. Zirconia spheres produced were further classified, calcined and modified with EDTPA to yield a solid-phase support for use in bio-chromatography (r_PEZ). Specifically, the ability of r_PEZ to selectively bind and enrich IgG, IgA, and IgM from biological fluids was evaluated and demonstrated. To better understand the force of interaction between the IgG and the r_PEZ, the equilibrium disassociation constant (K(d)) was determined by static binding isotherms, as a function of temperature and by frontal analysis at different linear velocities. The maximum static binding capacity (Q(max)) was found to be in the range 55-65 mg IgG per ml of beads, and unaffected by temperature. The maximum dynamic binding capacity (Q(x)) was found to be in the range 20-12 mg IgG per ml of beads. The adsorption rate constant (k(a)) was determined by a split-peak approach to be between 982 and 3242 l mol(-1) s(-1) depending on the linear velocity. The standard enthalpy and entropy values were estimated for this interaction of IgG with this novel support.

Chromatography, Liquid↗
PubMed2002

Identification of two SNPs in the 5' flanking region of the ACP1 gene and evaluation of disequilibrium among polymorphic sites.

We have studied the 5' flanking region of the ACP1 gene looking for new polymorphisms. Two SNPs, DdeI and FokI restricted, have been found in this region. We determined the genotype of DdeI and FokI SNPs, as well as of three other known SNPs, codon 43 (CfoI restricted), codon 41 and codon 105 (TaqI restricted), located respectively in exons 3, 4 and 6 in 62 unrelated subjects from the Italian population. Haplotype distribution for the ten possible pairs of loci were determined by a maximum likelihood procedure. Overall, statistically significant deviations from expected frequencies assuming equilibrium have been observed for the following pairs: FokI/codon 41, FokI/TaqI, codon 41/TaqI (complete association), DdeI/FokI, DdeI/codon 41 and DdeI/TaqI. The data suggest that the FokI area could include sequences operating in strict functional association with sequences included in the codon 41/TaqI area, possibly in order to regulate the F/S isoforms ratio of the A* and *B alleles. Since the ratio between the concentration of the two F and S isoforms is different for the three ACP1 alleles, we suggest that the ACP1 locus has been subjected to strong selective pressure to obtain an optimal alternative splicing mechanism of the *A and *B alleles. The *C variant, on the other hand, seems completely independent from sequences in the FokI/codon 41/TaqI areas, resulting in an inverted F/S ratio compared to that found for *A and *B alleles.

5' Flanking Region↗