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PubMed1984

Ethanolamine inhibits choline uptake in the isolated hamster heart.

The effect of exogenous ethanolamine on phosphatidylcholine biosynthesis in the isolated hamster heart was investigated. Hamster hearts were perfused with [Me-3H]choline in the presence of 0.05-0.5 mM ethanolamine. Incorporation of label into phosphatidylcholine was decreased 26-63% at 0.1-0.5 mM ethanolamine. Similar decreases in the labelling of the metabolites of the CDP-choline pathway were observed at these ethanolamine concentrations. The observed decrease in phosphatidylcholine labelling at 0.1-0.5 mM ethanolamine was attributed to an inhibition of labelled choline uptake by ethanolamine. The inhibitory role of ethanolamine to choline uptake was examined by comparison to hemicholinium-3. Both compounds inhibited choline uptake in a competitive manner. Intracellular choline, phosphocholine and CDP-choline concentrations were not altered under all experimental conditions. It can be concluded that exogenous ethanolamine has no immediate effect on the rate of phosphatidylcholine biosynthesis in the isolated hamster heart. The reduced labelling of phosphatidylcholine in the presence of ethanolamine is a direct result of the reduction of labelled choline taken up by the heart.

Animals↗
PubMed1986

Several lines of evidence demonstrating that Plasmodium falciparum, a parasitic organism, has distinct enzymes for the phosphorylation of choline and ethanolamine.

In Plasmodium falciparum-infected erythrocyte homogenates, the specific activity of ethanolamine kinase (7.6 +/- 1.4 nmol phosphoethanolamine/10(7) infected cells per h) was higher than choline kinase specific activity (1.9 +/- 0.2 nmol phosphocholine/10(7) infected cells per h). The Km of choline kinase for choline was 79 +/- 20 microM, and ethanolamine was a weak competitive inhibitor of the reaction (Ki = 92 mM). Ethanolamine kinase had a Km for ethanolamine of 188 +/- 19 microM, and choline was a competitive inhibitor of ethanolamine kinase with a very high Ki of 268 mM. Hemicholinium 3 inhibited choline kinase activity, but had no effect on ethanolamine kinase activity. In contrast, D-2-amino-1-butanol selectively inhibited ethanolamine kinase activity. Furthermore, when the two enzymes were subjected to heat inactivation, 85% of the choline kinase activity was destroyed after 5 min at 50 degrees C, whereas ethanolamine kinase activity was not altered. Our results indicate that the phosphorylation of choline and ethanolamine was catalyzed by two distinct enzymes. The presence of a de novo phosphatidylethanolamine Kennedy pathway in P. falciparum contributes to the bewildering variety of phospholipid biosynthetic pathways in this parasitic organism.

Amino Alcohols↗
PubMed1985

Transport of ethanolamine and its incorporation into the variant surface glycoprotein of bloodstream forms of Trypanosoma brucei.

The membrane-attached form of the variant surface glycoprotein (mf-VSG) of bloodstream forms of Trypanosoma brucei is anchored to the plasma membrane by a hydrophobic C-terminal lipo-oligosaccharide containing ethanolamine. Analysis by polyacrylamide gel electrophoresis showed that several different cloned T. brucei strains (strain EATRO 110 and variants 117 and 118 of strain 427) incorporated [3H]ethanolamine into both mf-VSG and the soluble VSG derived from it, but not into other proteins. Other trypanosomatids, e.g. Leishmania mexicana promastigotes, T. cruzi epimastigotes, and T. brucei procyclic forms, did not incorporate ethanolamine into cellular proteins. Thus, [3H]ethanolamine can be used as a specific biosynthetic label for T. brucei VSG polypeptides. The time course of incorporation of [3H]ethanolamine into VSG showed a lag period of about 15 min. Double-labelling experiments using [3H]ethanolamine and H3[32P]O4 demonstrated that ethanolamine labelled only the C-terminal moiety and was not incorporated into other portions of the VSG molecule. Cellular uptake of ethanolamine occurred via a specific carrier-mediated transport system having a Vmax of 132 pmol min-1 mg-1 protein and a Km of 3.7 microM. The properties of this transport system are consistent with the possibility that ethanolamine is derived entirely from the host.

Animals↗
PubMed1997

Ethanolamine modulates the rate of rat hepatocyte proliferation in vitro and in vivo.

A low molecular weight, heat-resistant hepatotrophic factor in an extract from the bovine intestinal mucosa was purified and identified as ethanolamine by structural analyses. The mode of action of ethanolamine in vitro and in vivo coincided with that of the crude extract of the tissue, indicating that ethanolamine is the active component. Ethanolamine synergistically elevated the stimulation of DNA synthesis in hepatocytes in primary culture when added together with a growth factor, such as epidermal growth factor, with the ED50 being 20 microM, although it showed little stimulatory effect by itself. Contrary to these in vitro results, the intraperitoneal administration of ethanolamine hydrochloride (24 mg of ethanolamine per kg of body weight) enhanced hepatocyte proliferation in regenerating rat livers after two-thirds hepatectomy without the administration of any growth factors. In the regenerating liver, hepatocyte proliferation may be initiated by an endogenous growth factor, but the supply of ethanolamine in circulation may not be sufficient for optimal hepatocyte proliferation; thus, the exogenous administration of ethanolamine may further enhance hepatocyte proliferation. Ethanolamine in circulation may be a humoral hepatotrophic factor.

Animals↗
PubMed1990

Effects of ethanolamine and choline on thiotepa cellular accumulation and cytotoxicity in L1210 cells.

The amino alcohols, ethanolamine and choline, were studied for their effects on (a) L1210 cell growth, (b) N,N',N"-triethylenetheiphosphoramide (thiotepa)-induced growth inhibition of L1210 cells, and (c) 14C accumulation by L1210 cells incubated with [14C]thiotepa. Ethanolamine, at concentrations up to 300 microM, had no effect on L1210 cell growth but, at concentrations greater than 300 microM, produced a dose-dependent reduction in cell growth. Choline, at concentrations up to 20 mM, had no effect on L1210 cell growth. Neither ethanolamine, at 250 microM, nor choline, at 10 mM, altered the ability of thiotepa to reduce L1210 cell growth. Neither ethanolamine, at 250 microM, nor choline, at 10 mM, affected the rapid phase of 14C accumulation by L1210 cells incubated with [14C]thiotepa. The slow phase of 14C accumulation by L1210 cells incubated with 5 microM [14C]thiotepa, a process which is 80-85% due to production of [14C]phosphatidylethanolamine, was not affected by 250 microM choline. In contrast, ethanolamine produced a dose-dependent reduction in this slow rate of 14C accumulation. The reduction in the slow rate of 14C accumulation produced by ethanolamine was due almost entirely to a decrease in the accumulation of nonexchangeable 14C. Kinetic analysis of the inhibition of 14C accumulation produced by 25, 100, and 250 microM ethanolamine was compatible with competitive inhibition. Thin layer chromatography of cell extracts showed that the ability of ethanolamine to reduce 14C accumulation by L1210 cells incubated with [14C]thiotepa was due solely to reduction in production of [14C]phosphatidylethanolamine. These results are all compatible with and predicted by our previously described scheme wherein thiotepa enters cells by simple diffusion and serves as a prodrug for aziridine, some of which is hydrolyzed to ethanolamine which is then incorporated into phosphatidylethanolamine via normal metabolic synthetic pathways.

Animals↗
PubMed1976

Phospholipid synthesis in mammary tissue. Choline and ethanolamine kinases: kinetic evidence for two discrete active sites.

Choline and ethanolamine kinases are located in the high speed supernatant of lactating bovine mammary gland. Maximum activities of choline and ethanolamine kinases were observed at pH 9.2 and 8.0, respectively, with the rate of ethanolamine phosphorylation being 1/15 that of choline phosphorylation. Activation energies of 29 joules (Q10--1.5) and 31 joules (Q10 = 1.5) were calculated between 3.4 and 31.3 C for choline kinase and ethanolamine kinase, respectively. Above 31.3 C, the Arrhenius plot deviated from linearity for both enzymes, suggesting that denaturation was occurring. An apparent Km of 0.25 mM for choline was obtained for choline kinase activity. The apparent Km of ethanolamine kinase for ethanolamine was unusually high (17 mM), the activity was not linear with increasing protein concentration. Activity was tripled and the Km decreased to 2.5 mM when the enzyme preparation was washed with butanol: benzene mixture, suggesting the presence of an endogenous competitive inhibitor(s), with respect to ethanolamine. Choline kinase was not affected by the solvent wash. Substrate competition studies revealed that choline kinase was slightly inhibited competitively by ethanolamine (apparent Ki = 19-21 mM), whereas choline was a potent competitive inhibitor of ethanolamine kinase (apparent Ki = 0.33-0.50 mM). The results indicated that these two kinase activities were mediated by two distinct active sites, possibly on a single protein. The significance of choline in the regulation of phosphatidylethanolamine synthesis is discussed.

Animals↗
PubMed2006

Improved absorption of meloxicam via salt formation with ethanolamines.

The present study aimed to investigate the effect of ethanolamine salt formation on the dissolution as well as in vivo pharmacokinetics of meloxicam. Three meloxicam-ethanolamine salts were prepared and their in vitro dissolution profiles were examined at pH 1.2 and 6.8. The pharmacokinetic profiles of meloxicam following an oral administration of meloxicam or its ethanolamine salts were also evaluated in rats. The dissolution rates of meloxicam and its ethanolamine salts were similarly slow at pH 1.2, however, at pH 6.8, ethanolamine salt formation significantly enhanced the dissolution rate of meloxicam. Meloxicam diethanolamine salt exhibited the highest dissolution rate at pH 6.8. The faster dissolution of meloxicam via ethanolamine salt formation at pH 6.8 appeared to be correlated well with more rapid absorption of meloxicam in rats. Tmax of meloxicam was significantly (p<0.05) shortened following an oral administration of ethanolamine salts. Furthermore, ethanolamine salts exhibited a trend toward the increase in AUC0-4 (initial exposure), while the overall exposure (AUC0-24) was similar between meloxicam and its salts. In conclusion, the ethanolamine salts of meloxicam, particularly diethanolamine salt of meloxicam, facilitated the rapid absorption of meloxicam while maintaining the prolonged exposure and may be used for the earlier onset of action for meloxicam.

Administration, Oral↗
PubMed1998

Effect of serine and ethanolamine administration on phospholipid-related compounds and neurotransmitter amino acids in the rabbit hippocampus.

The report concerns mechanisms for the increase of extracellular levels of ethanolamine and phosphoethanolamine in CNS regions, such as the hippocampus, in transient brain ischemia, hypoglycemia, seizures, etc. L-Serine (2.5-10 mM), D-serine (10 mM), or ethanolamine (10 mM) was administered for 20 min via a microdialysis tubing to the hippocampus of unanesthetized rabbits. The concentrations of primary amines were determined in the dialysates. When levels were elevated 10-100 times in the extracellular fluid, L-serine caused a dose-dependent increase of the concentration of extracellular ethanolamine. Ethanolamine caused a corresponding, although somewhat smaller, increase in serine levels. Furthermore, L-serine also induced an increased concentration of phosphoethanolamine that was delayed in time relative to the peak of ethanolamine. D-Serine was as effective as L-serine in raising ethanolamine levels but had no effect on phosphoethanolamine. Ethanolamine, but not L-serine, also increased extracellular glutamate/aspartate levels in an MK-801-dependent fashion. A similar effect, but delayed in time, was observed with D-serine. These effects were inhibited by MK-801. The concentrations of other amino acids were not significantly affected. The characteristics of the effects are suggestive of base exchange reactions between serine and ethanolamine and between ethanolamine and serine glycerophospholipids, respectively, in neuronal plasma membranes.

Amino Acids↗
PubMed2006

Regulation of the Saccharomyces cerevisiae EKI1-encoded ethanolamine kinase by zinc depletion.

Ethanolamine kinase catalyzes the committed step in the synthesis of phosphatidylethanolamine via the CDP-ethanolamine branch of the Kennedy pathway. Regulation of the EKI1-encoded ethanolamine kinase by the essential nutrient zinc was examined in Saccharomyces cerevisiae. The level of ethanolamine kinase activity increased when zinc was depleted from the growth medium. This regulation correlated with increases in the CDP-ethanolamine pathway intermediates phosphoethanolamine and CDP-ethanolamine, and an increase in the methylated derivative of phosphatidylethanolamine, phosphatidylcholine. The beta-galactosidase activity driven by the P(EKI1)-lacZ reporter gene was elevated in zinc-depleted cells, indicating that the increase in ethanolamine kinase activity was attributed to a transcriptional mechanism. The expression level of P(EKI1)-lacZ reporter gene activity in the zrt1deltazrt2delta mutant (defective in plasma membrane zinc transport) cells grown with zinc was similar to the activity expressed in wild-type cells grown without zinc. This indicated that EKI1 expression was sensitive to intracellular zinc. The zinc-mediated regulation of EKI1 expression was attenuated in the zap1delta mutant defective in the zinc-regulated transcription factor Zap1p. Direct interactions between Zap1p and putative zinc-responsive elements in the EKI1 promoter were demonstrated by electrophoretic mobility shift assays. Mutations of these elements to a nonconsensus sequence abolished Zap1p-DNA interactions. Taken together, this work demonstrated that the zinc-mediated regulation of ethanolamine kinase and the synthesis of phospholipids via the CDP-ethanolamine branch of the Kennedy pathway were controlled in part by Zap1p.

Enzyme Induction↗
PubMed2003

Dietary eritadenine and ethanolamine depress fatty acid desaturase activities by increasing liver microsomal phosphatidylethanolamine in rats.

The effects of eritadenine, a constituent of the Lentinus edodes mushroom, and ethanolamine, the base constituent of phosphatidylethanolamine (PE), on fatty acid desaturase activities and lipid profiles were investigated comparatively in rats. Rats were fed a control diet or a diet supplemented with either eritadenine (0.05 g/kg) or ethanolamine (8 g/kg) for 14 d. Eritadenine and ethanolamine had marked hypocholesterolemic effects. The concentration of liver microsomal PE was significantly increased and the ratio of phosphatidylcholine (PC) to PE was significantly decreased by both eritadenine and ethanolamine. These changes in phospholipid profile were also observed in the mitochondria and plasma membranes in the liver. The activities of the Delta5-, Delta6- and Delta9-desaturases in liver microsomes were significantly decreased by eritadenine and ethanolamine; there was a significant correlation between the activity of Delta5- or Delta6-desaturase and the proportion of PE in the total phospholipids or the PC/PE ratio. Reflecting decreased Delta5- and Delta6-desaturase activities, the 20:4(n-6)/18:2(n-6) ratio was significantly decreased by eritadenine and ethanolamine in PC of the liver microsomes, mitochondria and plasma membranes. Although the 20:4(n-6)/18:2(n-6) ratio of liver microsomal PE was also significantly decreased by eritadenine and ethanolamine, the fatty acid composition of phosphatidylinositol and phosphatidylserine was less affected by these compounds. Eritadenine and ethanolamine increased the proportion of 16:0-18:2 and decreased the proportion of 18:0-20:4 in liver PC. The results suggest that dietary eritadenine and ethanolamine might lead to decreases in desaturase activities and changes in fatty acid and molecular species composition of PC through an increase in liver microsomal PE.

Adenine↗
PubMed2004

A pH-sensitive function and phenotype: evidence that EutH facilitates diffusion of uncharged ethanolamine in Salmonella enterica.

The eutH gene is part of an operon that allows Salmonella enterica to use ethanolamine as a sole source of nitrogen, carbon, and energy. Although the sequence of EutH suggests a role in transport, eutH mutants use ethanolamine normally under standard conditions (pH 7.0). These mutants fail to use ethanolamine at a low pH. Evidence is presented that protonated ethanolamine (Eth0) does not enter cells, while uncharged ethanolamine (Eth0) diffuses freely across the membrane. The external concentration of Eth0 varies with the pH (pK=9.5). At pH 7.0, the standard ethanolamine concentration (41 mM) provides enough Eth0 for an influx rate that can support growth with or without EutH. When a lowered pH and/or ethanolamine concentration reduced the Eth0 concentration below 25 microM, EutH was needed to facilitate diffusion. EutH+ cells grew normally at Eth0 concentrations above 3 microM, close to the Km (9 microM) of the first degradative enzyme, ethanolamine ammonia lyase. It is suggested that EutH facilitates diffusion of Eth0. As predicted for a transporter, EutH contributed to the toxicity of ethanolamine seen under some conditions; furthermore, fusion of EutH to fluorescent Yfp protein provided evidence that EutH is a membrane protein.

Bacterial Proteins↗
PubMed1975

Changes in metabolism of ethanolamine and its derivatives in liver during fasting.

The time course of incorporation of radioactivity into liver phosphatidylethanolamine and its precursors was studied following intraportal injection of [1,2-14C]ethanolamine into rats that had been fasted for 24 h and into nonfasted rats. Marked diminution in the labelling of liver phosphatidylethanolamine and CDP-ethanolamine was present in the fasted groups while the radioactivity contained in the ethanolamine and phosphorylethanolamine pools of these livers was increased. The livers of the fasted rats contained significantly higher levels of ethanolamine, phosphorylethanolamine and CDP-ethanolamine while choline and phosphorylcholine were decreased. These changes are identical to those which we have described earlier in the livers of nonfasted rats fed a choline deficient diet. In a further experiment, the duration of the fasting period necessary to bring about these changes was studied. Incorporation of radioactivity into liver phosphatidylethanolamine at 2.5 min following intraportal injection of [1,2-14]ethanolamine declined progressively up to 7.5 h of fasting and did not decrease further after that time. There was a concomitant decrease in labelling of CDP-ethanolamine with retention of radioactivity in ethanolamine and phosphorylethanolamine. These results show that the liver metabolism of ethanolamine is altered quite early in the fasting period and suggest that it may be related in some way to the metabolic response to fasting.

Animals↗
PubMed1989

Synthesis of Ethanolamine and Its Regulation in Lemna paucicostata.

The metabolism of ethanolamine and its derivatives in Lemna paucicostata has been investigated, with emphasis on the path-way for synthesis of phosphoethanolamine, a precursor of phosphatidylcholine in higher plants. In experiments involving labeling of intact plants with radioactive serine, ambiguities of interpretation due to entry of radioactivity into methyl groups of methylated ethanolamine derivatives were mitigated by pregrowth of plants with methionine. Difficulties due to labeling of diacylglyceryl moieties of phospholipids were avoided by acid hydrolysis of crucial samples and determination of radioactivity in isolated serine or ethanolamine moieties. The results obtained from such experiments are most readily reconciled with the biosynthetic sequence: serine --> ethanolamine --> phosphoethanolamine --> phosphatidylethanolamine. A possible alternative is: serine --> phosphatidylserine --> phosphatidylethanolamine --> ethanolamine --> phosphoethanolamine. Cell-free extracts of L. paucicostata were shown to produce CO(2) from the carbon originating as C-1 of serine at a rate sufficient to satisfy the demand for ethanolamine moieties. A number of experiments produced no support for a hypothetical role for phosphoserine in phosphoethanolamine formation. Uptake of exogenous ethanolamine commensurately down-regulates the synthesis of ethanolamine moieties (considered as a whole, and regardless of their state of derivatization at the time of their formation). In agreement with previous observations, uptake of exogenous choline down-regulates the methylation of phosphoethanolamine, without being accompanied by secondary accumulation of a marked excess of ethanolamine derivatives.

Journal Article↗
PubMed1969

Acyl and alk-1-enyl group compositions of the alk-1'-enyl acyl and the diacyl glycerophosphoryl ethanolamines of mouse and ox brain.

The ethanolamine phosphoglycerides were prepared from lipid extracts of ox and mouse brains by preparative thin-layer chromatography. The cyclic acetal derivatives of the alk-1-enyl groups were made by treating the ethanolamine phosphoglycerides with 1,3-propanediol. The resulting monoacyl glycerophosphoryl ethanolamines were separated from the unchanged ethanolamine phosphoglycerides by preparative thin-layer chromatography. Methyl ester derivatives of the acyl groups from both of these fractions were prepared by alkaline methanolysis. The cyclic acetal and methyl ester derivatives were analyzed by gas-liquid chromatography. Substantial differences were found in the composition of the side chains when the combined alk-1-enyl and acyl side chains of the alk-1'-enyl acyl glycerophosphoryl ethanolamines were compared with the side chains of the diacyl glycerophosphoryl ethanolamines. The side chains from the 1-position of these two ethanolamine phosphoglycerides are different in chain length and unsaturation as well as in chemical bonding. The acyl groups from the 2-position of the alk-1'-enyl acyl glycerophosphoryl ethanolamines were predominantly unsaturated. Therefore, acyl group compositions of the total ethanolamine phosphoglyceride from brain are of limited value and individual types should be analyzed.

Amino Alcohols↗
PubMed1978

Microbial metabolism of amino alcohols. Purification and properties of coenzyme B12-dependent ethanolamine ammonia-lyase of Escherichia coli.

1. The 120-fold purification of ethanolamine ammonia-lyase from Escherichia coli extracts, to apparent homogeneity, is described. Ethanolamine, dithiothreitol, glycerol and KCl protected the apoenzyme from inactivation. 2. At the optimum pH7.5, K(m) values for ethanolamine and coenzyme B(12) were 44mum and 0.42mum respectively. The K(m) for ethanolamine was markedly affected by pH, transitions occurring at pH7.0 and 8.35. 3. The enzyme was specific for ethanolamine as substrate, none of the 18 analogues tested being active. l-2-Aminopropan-l-ol (K(i) 0.86mum), dl-1-aminopropan-2-ol (K(i) 2.2mum) and dl-1,3-diaminopropan-2-ol (K(i) 88.0mum) inhibited competitively. 4. Enzyme activity was inhibited, irreversibly and non-competitively, by the coenzyme analogues methylcobalamin (K(i) 1.4nm), hydroxocobalamin (K(i) 2.1nm) and cyanocobalamin (K(i) 4.8nm). 5. Iodoacetamide inhibited in the absence of ethanolamine, but only slightly in its presence. p-Hydroxymercuribenzoate inhibited markedly even in the presence of ethanolamine. Dithiothreitol and 2-mercaptoethanol (less effectively) restored activity to the enzyme dialysed against buffer containing ethanolamine. 6. Although K(+) ions stabilized the enzyme during dialysis or storage, they were not necessary for activity. 7. Gel filtration showed the enzyme to be of high molecular weight, ultracentrifugal studies giving s(20,w) of 16.4 and an estimated mol.wt. 560400. The isoelectric point for the apoenzyme was approx. pH5.0. inhibited enzyme activity at concentrations above 1m (95% inhibition at 3m) and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated protein subunits of mol.wt. 61400. 8. Immunological studies showed that the E.coli enzyme was closely related to those of other enterobacteria, but only distantly to that of Clostridium sp. A double precipitin band suggested that the apoenzyme may be made up of two protein components.

Ammonia-Lyases↗
PubMed1978

Microbial metabolism of amino alcohols. Formation of coenzyme B12-dependent ethanolamine ammonia-lyase and its concerted induction in Escherichia coli.

1. Kinetic studies of ethanolamine ammonia-lyase formation by Escherichia coli suggested that coenzyme B12 (5'-deoxyadenosylcobalamin), with ethanolamine, is a co-inducer. 2. Enzymic and immunological tests failed to show the formation of complementary enzyme components induced separately by ethanolamine and cobalamin respectively. 3. Although specific for ethanolamine as the substrate, enzyme formation was induced by certain analogues, e.g. 2-aminopropan-1-ol. 4. Experiments with cyano[57Co]-cobalamin suggested that neither coenzyme B12 nor some more tightly bound coenzymically inactive cobamide was necessary for enzyme stability in vitro. 5. Mutants of E. coli were obtained which formed ethanolamine ammonia-lyase apoenzyme constitutively, showing that neither ethanolamine nor cobalamin was required for assembly or post-transcriptional stability of the enzyme in vivo. Constitutive enzyme formation was subject to catabolite repression, particularly by glucose. 6. It appears likely that ethanolamine and coenzyme B12, acting in concert, induce ethanolamine ammonia-lyase formation. The term 'concerted' induction is proposed for this phenomenon.

Ammonia-Lyases↗
PubMed1991

Analysis of cytosolic phosphoethanolamine and ethanolamine and their correlation with prognostic factors in breast cancer.

Availability of accurate prognostic factors is vital in making decisions on cancer therapy. We have measured the cytosolic contents of phosphoethanolamine and ethanolamine in tumor tissues of 53 breast cancer patients in an attempt to explore the possibility that these amines could be used as prognostic indicators. The levels of phosphoethanolamine and ethanolamine were determined by high-performance liquid chromatography. The ratios of the molar quantity of these amines or amino acids to that of alanine plus tyrosine, which eluted as a single peak, were used to analyze and compare the results among different tumor samples. The results indicated that the values for phosphoethanolamine or ethanolamine varied significantly more than the values for amino acids, such as glycine plus threonine or glutamine plus serine (these amino acids were eluted as single peaks, respectively). The values for phosphoethanolamine, ethanolamine, and phosphoethanolamine plus ethanolamine were analyzed in relation to several commonly used prognostic factors of breast disease. The results indicated that groups having higher mitotic indices had significantly higher values for phosphoethanolamine or phosphoethanolamine plus ethanolamine than the group having lower mitotic indices. As the stage of the disease increased, the values for phosphoethanolamine plus ethanolamine also seemed to become higher. No correlation, however, was observed between steroid hormone receptor positive and negative groups or between positive and negative groups with regard to involved axillary lymph nodes. The content of phosphoethanolamine or phosphoethanolamine plus ethanolamine in cytosol therefore seems to be correlated with some prognostic indicators.

Amino Acids↗
PubMed1992

Complexity of ethanolamine phosphate addition in the biosynthesis of glycosylphosphatidylinositol anchors in mammalian cells.

Biosynthetic intermediates for the mammalian glycosylphosphatidylinositol (GPI) anchor have been described. The earliest GPI anchor precursor is N-acetylglucosaminylphosphatidylinositol, which is deacetylated to give glucosaminylphosphatidylinositol. This is followed by fatty acylation of the inositol ring, sequential addition of mannose residues donated by dolichyl mannosyl phosphate, and finally addition of ethanolamine phosphate. Here, we show that the final steps of GPI anchor biosynthesis are more complex than we have previously reported. Six distinct GPI anchor precursors were found to contain at least 1 ethanolamine phosphate residue. The headgroups of these glycolipids were purified and analyzed by a combination of Bio-Gel P4 chromatography and high resolution thin-layer chromatography. The sizes of neutral glycans were determined following HF dephosphorylation. The position of the ethanolamine phosphate residue was inferred from results of alpha-mannosidase treatment. Finally, the number of negative charges on the headgroups were determined by Mono Q chromatography. Our results show that the addition of ethanolamine phosphate is controlled by at least two different genes. Thus, the class F mutant, though unable to add ethanolamine phosphate to the third mannose residue, does incorporate ethanolamine phosphate into the first and second mannose residues. Only the wild type cells are capable of incorporating ethanolamine phosphate into the third mannose residue. Furthermore, the GPI core contains up to 3 ethanolamine phosphate residues. These results should facilitate the elucidation of the biochemical defects in paroxysmal nocturnal hemoglobinuria.

Animals↗