Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SERINE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1991

Structural and functional roles of highly conserved serines in human lipoprotein lipase. Evidence that serine 132 is essential for enzyme catalysis.

The structure of human lipoprotein lipase was recently deduced from its cDNA sequence. It contains 8 serine residues (residues 45, 132, 143, 172, 193, 244, 251, and 363) that are absolutely conserved in both lipoprotein lipase and hepatic lipase across all species studied. The high homology between lipoprotein lipase, hepatic lipase, and pancreatic lipase suggests that the catalytic functions of these enzymes share a common mechanism and that one of the 8 conserved serines in human lipoprotein lipase must play a catalytic role as does serine 152 in the case of pancreatic lipase (Winkler, F. K., D'Arcy, A., and Hunziker, W. Nature 343, 771-774). We expressed wild-type and site-specific mutants of human lipoprotein lipase in COS cells in vitro. We produced two to four substitution mutants involving each of the 8 serines and assayed a total of 22 mutants for both enzyme activity and the amount of immunoreactive enzyme mass produced. Immunoreactive lipase was detected in all cases. With the exception of Ser132, for each of the 8 serine mutants we studied, at least one of several mutants at each position showed detectable enzyme activity. All three substitution mutants at Ser132, Ser----Thr, Ser----Ala, and Ser----Asp, were totally inactive. Ser132 occurs in the consensus sequence Gly-Xaa-Ser-Xaa-Gly present in all serine proteinases and in human pancreatic lipase. The x-ray crystallography structure of human pancreatic lipase suggests that the analogous serine residue in human pancreatic lipase, Ser152, is the nucleophilic residue essential for catalysis. Our biochemical data strongly support the conclusion that Ser132 in human lipoprotein lipase is the crucial residue required for enzyme catalysis. The observed specific activities of the variants involving the other seven highly conserved serines in human lipoprotein lipase are consistent with the interpretation that this enzyme has a three-dimensional structure very similar to that of human pancreatic lipase.

Amino Acid Sequence↗
PubMed1976

[Formation of the prothrombin-phosphatidyl serine and thrombin-phosphatidyl serine complex].

A possibility of formation of the thrombin-phosphatidyl serine and prothrombin-phosphatidyl serine complex is discussed. Prothrombin incubation with 131J-labelled phosphatidyl serine and its subsequent activation results in a formation of a thrombin-phosphatidyl serine--131J-complex. The radioactive label is also detected in the protein precipitate after thermodenaturation of thrombin preincubated with 131J-labelled phosphatidyl serine, which suggests that thrombin is firmly bound to phosphatidyl serine. The formation of the thrombin-phosphatidyl serine and prothrombin-phosphatidyl serine complex is supported by data of gel-filtration on Sephadex G-200 and acrylexes P-150 and P-60, as well as by differential spectrophotometry.

Chemical Phenomena↗
PubMed2003

D-serine and serine racemase are present in the vertebrate retina and contribute to the physiological activation of NMDA receptors.

d-serine has been proposed as an endogenous modulator of N-methyl-d-aspartate (NMDA) receptors in many brain regions, but its presence and function in the vertebrate retina have not been characterized. We have detected d-serine and its synthesizing enzyme, serine racemase, in the retinas of several vertebrate species, including salamanders, rats, and mice and have localized both constituents to Müller cells and astrocytes, the two major glial cell types in the retina. Physiological studies in rats and salamanders demonstrated that, in retinal ganglion cells, d-serine can enhance excitatory currents elicited by the application of NMDA, as well as the NMDA receptor component of light-evoked synaptic responses. Application of d-amino acid oxidase, which degrades d-serine, reduced the magnitude of NMDA receptor-mediated currents, raising the possibility that endogenous d-serine serves as a ligand for setting the sensitivity of NMDA receptors under physiological conditions. These observations raise exciting new questions about the role of glial cells in regulating the excitability of neurons through release of d-serine.

Animals↗
PubMed1978

A D-serine dehydratase acting also on L-serine from Klebsiella pneumoniae.

D-Serine dehydratase [EC 4.2.1.14] was purified from a strain of Klebsiella pneumoniae 140-fold from crude extract with a yield of 5%. This enzyme catalyzed formation of pyruvate and ammonia not only from D-serine but also from L-serine, and also catalyzed the formation of alpha-ketobutyrate and ammonia from D-threonine. Km values for D-serine, L-serine, and D-threonine were 2.8 mM, 20 mM, and 3.6 mM, respectively. Km for pyridoxal 5'-phosphate was 2.5 micron. The molecular weight was estimated to be 46,000 by Sephadex G-150 gel filtration and 40,000 by SDS-polyacrylamide gel electrophoresis. This enzyme was inducible by D-serine. Induction by casamino acids appeared to depend on the presence of D-serine.

Enzyme Induction↗
PubMed1993

Cancer-associated SCM-recognition, immunedefense suppression, and serine protease protection peptide. Part III. CRISPP peptide protection of serine proteases against inhibition.

The cancer SCM-recognition, immunedefense suppression, and serine protease protection (CRISPP) peptide, produced by cancer cells, is homologous to the Pn', enzyme-baiting region of the serine protease inhibitor alpha 1-PI. In contrast to the inhibitory function of the intact alpha 1-PI, the CRISPP peptide protects cancer-associated serine proteases against inhibition by alpha 1-PI. In the presence of alpha 1-PI, the prevention of inhibition is a competitive, concentration-dependent process. The shortest fragment of the 29 amino acid sequence of the synthetic, CRISPPs peptide, which protects serine proteases against inhibition as efficiently as the whole molecule, encompasses the amino terminal amino acid residues 1 to 7. Serine proteases and their inhibitor, alpha 1-PI, are involved in the control of many intra- and extracellular physiological processes, including degradative actions in cancer cell invasion, metastatic spread, and neovascularization of tumors. The CRISPP peptide protection of serine proteases against inhibition could unbalance the regulatory controls requiring limited proteolysis by serine proteases. The inherited and/or acquired aberrations resulting in the production of CRISPP peptides in cancer cells could, therefore, be one of the key factors involved in the carcinogenic transformation, enhancing uncontrolled gene derepression and DNA synthesis, and supporting invasion and metastasis. A hypothesis on the mechanism of CRISPP peptide action is proposed.

Epitopes↗
PubMed1994

Characterization of the serine protease and serine protease inhibitor from the tissue-penetrating nematode Anisakis simplex.

A serine protease and a serine protease inhibitor were purified from infective larvae of the parasitic nematode Anisakis simplex. The serine protease was found to be trypsin-like and preferentially cleaved substrates with the basic amino acid arginine at the P1 position (Z-Gly-Pro-Arg-AMC (where Z is benzyloxycarbonyl), Km = 0.019 mM, and Z-Phe-Pro-Arg-AMC, Km = 0.013 mM) at rates similar to those determined for trypsin (0.002 mM and 0.006 mM, respectively). However, the presence of a bulky hydrophobic residue at the P2 position (Z-Phe-Arg-AMC, Km = 13.3 mM, and Z-Ile-Leu-Val-Arg-AMC, Km = 24.7 mM) greatly decreased the rate of substrate hydrolysis. Internal amino acid sequence information was obtained from three endo Lys-C digestion fragments of the purified enzyme. These sequences were > 89% (33:37) identical with that of porcine trypsin. A second serine protease 85% (11:13) identical with that of a secreted tissue-destructive serine protease from the pathogenic bacterium Dichelobacter nodosus was also identified. The serine protease inhibitor was found to inhibit trypsin, elastase, and the Anisakis serine protease stoichiometrically, but did not inhibit chymotrypsin. The amino acid sequence of the amino terminus as well as two internal endo Lys-C fragments were determined. Approximately 96% (47:49) of the residues were identical with soybean trypsin inhibitor, indicating that this inhibitor belongs to the Kunitz-type family of inhibitors.

Amino Acid Sequence↗
PubMed1980

Effect of methionine, glycine and serine on serine hydroxymethyltransferase activity in rat glioma and human neuroblastoma cells.

Human neuroblastoma SK-N-SH-SY5Y (5Y) and rat glioma (C6) cells were cultured with supplemental methionine, glycine, or serine for three to six days. Serine hydroxmethyltransferase (SHMT: L-serine: tetrahydrofolate 5, 10-hydroxymethyltransferase, EC 2.12.1) was assayed radiometrically in whole cell homogenates, crude supernatant fractions and crude particulate fractions. No significant changes in specific activity or cellular morphology were noted at methionine, glycine, or serine concentrations up to 16 mM. Serine concentrations of 20 and 40 mM led to significantly lower gliomal enzyme specific activities. This activity was unevenly distributed between soluble and particulate fractions, with 190 and 398 nmoles of HCHO formed per mg of protein per hour, respectively. Growth stage and time of incubation were major determinants of enzyme specific activity. C6 cells' specific activity rose slowly with increasing time in culture until cellular confluence. At this time there was a pronounced elevation in specific activity, occurring more rapidly in cells grown in 1.2 mM methionine. Intracellular amino acid analysis of C6 cells demonstrated a significant rise in methionine after four days in media containing 0.2 mM methionine. No appreciable diminution in the intracellular levels of glycine or serine occurred following incubation in excess methionine. It is concluded that SHMT-specific activity in C6 and 5Y cells is not regulated by glycine, serine, or methionine levels and that high concentrations of these amino acids (> 30 mM) are not detrimental to these cells derived from the CNS.

Animals↗
PubMed1999

The p38MAPK inhibitor SB203580 alleviates ultraviolet-induced phosphorylation at serine 389 but not serine 15 and activation of p53.

Phosphorylation of p53 at serine 389 has been shown to be responsive uniquely to UV but not gamma irradiation. This report describes identification of the UV-responsive p38MAPK protein as a serine 389 kinase. The immunoprecipitated p38MAPK from UV-irradiated murine embryonic testicular carcinoma F9 cells phosphorylated the serine 392 residue but not serine 15 of the human p53 protein in vitro and this phosphorylation was inhibited by a p38MAPK-specific chemical inhibitor SB203580. The inhibitor also remarkably alleviated the UV-caused induction and serine 389 but not serine 15 phosphorylation of the murine p53 protein in vivo. Subsequently, this compound suppressed transcriptional activity of p53 and partially retarded UV-induced apoptosis. Moreover, p53 bound to p38 as revealed by immunoprecipitation with anti-p53 antibodies from UV-treated F9 cells. Thus, these results suggest that UV-stimulated p53 phosphorylation at serine 389 is mediated by the stress-responsive p38MAPK.

Animals↗
PubMed1994

The serine receptor of bacterial chemotaxis exhibits half-site saturation for serine binding.

Ligand binding to the serine receptor of Escherichia coli has been studied using isothermal titration calorimetry. Bacterial inner membranes enriched in the serine receptor (Tsr) were titrated as sonicated membrane samples and after solubilization in octyl beta-D-glucopyranoside (OG) to determine the number of moles of ligand bound per mole of receptor (n), the binding constant (Ka), and the enthalpy of binding (delta H) of serine to the receptor. The n value for serine binding to OG-solubilized Tsr protein (n = 0.5) was consistent with one molecule of serine binding to a receptor dimer, but in sonicated inner membrane samples, the n value was smaller (n approximately equal to 0.25), indicating that not all of the binding sites were accessible to added serine. At 7 and 27 degrees C, the values for Ka and delta H were equivalent for the membrane and OG-solubilized samples and were found to be 4.7 x 10(4) M-1 and -15 kcal/mol, and 3.6 x 10(4) M-1 and -18 kcal/mol, respectively. The influence of covalent modification at the sites of methylation on the affinity of the receptor for serine was also investigated, and found to have only a modest effect. The property of half-site saturation is suggestive of models for transmembrane signaling where the receptor subunit interactions are modulated by ligand binding.

Calorimetry↗
PubMed2003

Disruption of the SHM2 gene, encoding one of two serine hydroxymethyltransferase isoenzymes, reduces the flux from glycine to serine in Ashbya gossypii.

Riboflavin overproduction in the ascomycete Ashbya gossypii is limited by glycine, a precursor of purine biosynthesis, and therefore an indicator of glycine metabolism. Disruption of the SHM 2 gene, encoding a serine hydroxymethyltransferase, resulted in a significant increase in riboflavin productivity. Determination of the enzyme's specific activity revealed a reduction from 3 m-units/mg of protein to 0.5 m-unit/mg protein. The remaining activity was due to an isoenzyme encoded by SHM 1, which is probably mitochondrial. A hypothesis proposed to account for the enhanced riboflavin overproduction of SHM 2-disrupted mutants was that the flux from glycine to serine was reduced, thus leading to an elevated supply with the riboflavin precursor glycine. Evidence for the correctness of that hypothesis was obtained from (13)C-labelling experiments. When 500 microM 99% [1-(13)C]threonine was fed, more than 50% of the label was detected in C-1 of glycine resulting from threonine aldolase activity. More than 30% labelling determined in C-1 of serine can be explained by serine synthesis via serine hydroxymethyltransferase. Knockout of SHM 1 had no detectable effect on serine labelling, but disruption of SHM 2 led to a decrease in serine (2-5%) and an increase in glycine (59-67%) labelling, indicating a changed carbon flux.

Amino Acid Sequence↗
PubMed1998

Phosphatidylinositol 3'-kinase associates with an insulin receptor substrate-1 serine kinase distinct from its intrinsic serine kinase.

Serine phosphorylation of insulin receptor substrate-1 (IRS-1) has been proposed as a counter-regulatory mechanism in insulin and cytokine signalling. Here we report that IRS-1 is phosphorylated by a wortmannin insensitive phosphatidylinositol 3'-kinase (PI 3-kinase)-associated serine kinase (PAS kinase) distinct from PI 3-kinase serine kinase. We found that PI 3-kinase immune complexes contain 5-fold more wortmannin-insensitive serine kinase activity than SH2-containing protein tyrosine phosphatase-2 (SHP2) and IRS-1 immune complexes. Affinity chromatography of cell lysates with a glutathione S-transferase fusion protein for the p85 subunit of PI 3-kinase showed that PAS kinase associated with the p85 subunit of PI 3-kinase. This interaction required unoccupied SH2 domain(s) but did not require the PI 3-kinase p110 subunit binding domain. In terms of function, PAS kinase phosphorylated IRS-1 and, after insulin stimulation, PAS kinase phosphorylated IRS-1 in PI 3-kinase-IRS-1 complexes. Phosphopeptide mapping showed that insulin-dependent in vivo sites of IRS-1 serine phosphorylation were comparable to those of PAS kinase phosphorylated IRS-1. More importantly, PAS kinase-dependent phosphorylation of IRS-1 reduced by 4-fold the ability of IRS-1 to act as an insulin receptor substrate. Taken together, these findings indicate that: (a) PAS kinase is distinct from the intrinsic serine kinase activity of PI 3-kinase, (b) PAS kinase associates with the p85 subunit of PI 3-kinase through SH2 domain interactions, and (c) PAS kinase is an IRS-1 serine kinase that can reduce the ability of IRS-1 to serve as an insulin receptor substrate.

Androstadienes↗
PubMed1999

Purification of serine racemase: biosynthesis of the neuromodulator D-serine.

High levels of D-serine occur in mammalian brain, where it appears to be an endogenous ligand of the glycine site of N-methyl-D-aspartate receptors. In glial cultures of rat cerebral cortex, D-serine is enriched in type II astrocytes and is released upon stimulation with agonists of non-N-methyl-D-aspartate glutamate receptors. The high levels of D-serine in discrete areas of rat brain imply the existence of a biosynthetic pathway. We have purified from rat brain a soluble enzyme that catalyzes the direct racemization of L-serine to D-serine. Purified serine racemase has a molecular mass of 37 kDa and requires pyridoxal 5'-phosphate for its activity. The enzyme is highly selective toward L-serine, failing to racemize any other amino acid tested. Properties such as pH optimum, Km values, and the requirement for pyridoxal phosphate resemble those of bacterial racemases, suggesting that the biosynthetic pathway for D-amino acids is conserved from bacteria to mammalian brain.

Amino Acid Isomerases↗
PubMed2005

Effect of pressure on the crystal structure of L-serine-I and the crystal structure of L-serine-II at 5.4 GPa.

The crystal structure of L-serine has been determined at room temperature at pressures between 0.3 and 4.8 GPa. The structure of this phase (hereafter termed L-serine-I), which consists of the molecules in their zwitterionic tautomer, is orthorhombic, space group P212121. The least compressible cell dimension (c), corresponds to chains of head-to-tail NH...carboxylate hydrogen bonds. The most compressible direction is along b, and the pressure-induced distortion in this direction takes the form of closing up voids in the middle of R-type hydrogen-bonded ring motifs. This occurs by a change in the geometry of hydrogen-bonded chains connecting the hydroxyl groups of the -CH2OH side chains. These hydrogen bonds are the longest conventional hydrogen bonds in the system at ambient pressure, having an O...O separation of 2.918 (4) A and an O...O...O angle of 148.5 (2) degrees ; at 4.8 GPa these parameters are 2.781 (11) and 158.5 (7) degrees . Elsewhere in the structure one NH...O interaction reaches an N...O separation of 2.691 (13) A at 4.8 GPa. This is amongst the shortest of this type of interaction to have been observed in an amino acid crystal structure. Above 4.8 GPa the structure undergoes a single-crystal-to-single-crystal phase transition to a hitherto uncharacterized polymorph, which we designate L-serine-II. The OH...OH hydrogen-bonded chains of L-serine-I are replaced in L-serine-II by shorter OH...carboxyl interactions, which have an O...O separation of 2.62 (2) A. This phase transition occurs via a change from a gauche to an anti conformation of the OH group, and a change in the NCalphaCO torsion angle from -178.1 (2) degrees at 4.8 GPa to -156.3 (10) degrees at 5.4 GPa. Thus, the same topology appears in both crystal forms, which explains why it occurs from one single-crystal form to another. The transition to L-serine-II is also characterized by the closing-up of voids which occur in the centres of other R-type motifs elsewhere in the structure. There is a marked increase in CH...O hydrogen bonding in both phases relative to L-serine-I at ambient pressure.

Crystallography↗
PubMed1979

Serine hydroxymethyltransferase activity and serine incorporation in leukocytes.

Studies of serine hydroxymethyltransferase activity in extracts of leukocytes from normal and leukemic subjects showed that the enzyme is present in lymphocytes and granulocytes but that activity is higher in lymphocytes. It is also higher than normal in lymphocytes from patients with chronic lymphocytic leukemia and to a lesser extent in the leukocytes of patients with acute myelocytic leukemia and acute lymphocytic leukemia. A striking increase in activity occurs in lymphocytes stimulated by phytohemagglutinin to divide in culture. Enzyme activity rises severalfold before cell number increases. Stimulated lymphocytes take up [3-14C]serine from the medium and incorporate its radioactivity into DNA, RNA, and other cell fractions. The rate of incorporation increases sharply before the rise in cell number. Thus, serine hydroxymethyltransferase activity and serine incorporation in vivo show a temporal correlation in stimulated lymphocytes. Inhibitors of DNA synthesis (e.g., fluorodeoxyuridine or high concentrations of adenosine or thymidine) block incorporation of serine radioactivity into DNA and other cell fractions. The results suggest that serine hydroxymethyltransferase activity and cellular uptake of serine have a significant role in proliferating cells.

DNA↗
PubMed1983

l-Serine Production by a Mutant of Sarcina albida Defective in l-Serine Degradation.

For improved l-serine production, an l-serine dehydratase-defective mutant of Sarcina albida IAM 1012 was obtained. In the mutant, the activities of the enzymes responsible for l-serine production were as high as those in the parent strain, and, at a low glycine concentration, the mutant accumulated l-serine more efficiently than the parent. Under optimum conditions, 21 mg of l-serine per ml accumulated from 100 mg of glycine per ml. l-Serine was isolated from a reaction mixture as l-serine m-xylene-4-sulfonate, and free amino acid was obtained in high yields by use of an ion-exchange resin. Residual glycine was recovered at a yield of 61%.

Journal Article↗
PubMed2004

Serine proteases in the spiny lobster olfactory organ: their functional expression along a developmental axis, and the contribution of a CUB-serine protease.

Several serine proteases and protease inhibitors have been identified in the crustacean olfactory organ, which is comprised of the lateral flagellum of the antennule and its aesthetascs sensilla that house olfactory receptor neurons and their supporting cells. The function of these proteases in the olfactory organ is unknown, but may include a role in perireception (e.g., odor activation or inactivation) or in the development or survival of olfactory receptor neurons. To examine directly the function of proteases in the olfactory organ of the Caribbean spiny lobster Panulirus argus, we used different tissue fractions from the lateral flagellum in an enzyme activity assay with a variety of protease substrates and inhibitors. Trypsin-like serine protease activity occurs throughout the lateral flagellum but is enriched in the cell membranes from aesthetascs. Cysteine- and metalloprotease activities also occur in olfactory tissue, but are more abundant in tissue fractions other than aesthetascs. To assess the contribution of one of the olfactory serine proteases--CUB-serine protease (Csp)--Csp was immunoprecipitated using an antibody; results with the remaining fraction suggest that Csp accounts for at least 40% of the total serine protease activity in the olfactory organ. The amount of total serine protease activity follows a developmental axis in the lateral flagellum. Total protease activity is lowest in the proximal zone, which lacks aesthetascs, and the proliferation zone, where olfactory receptor neurons and associated cells are born, and highest in aesthetascs of the distally-located senescence zone, which has the oldest olfactory tissue.

Animals↗
PubMed1993

Enzymatic assay for L-serine and glyoxylate involving the enzymes in the serine pathway of a methylotroph.

An easy, rapid, and accurate enzymatic assay method for L-serine was established involving two enzymes, serine-glyoxylate aminotransferase (SGAT, EC 2.6.1.45) and hydroxypyruvate reductase (HPR, EC 1.1.1.81), in the serine pathway of the methylotrophic bacterium, Hyphomicrobium methylovorum (IFO 14180), from which they were purified. This method consists of two reaction steps: the first is the nearly irreversible transamination of L-serine and glyoxylate by SGAT, and the second is the HPR reaction involving NADH, which comprises the absolutely irreversible reduction of hydroxypyruvate derived from L-serine by SGAT. The amounts of L-serine were determined spectrophotometrically as the decrease in the amount of NADH. When the values determined with the present enzymatic method were compared with those obtained with an amino acid analyzer, the correlation coefficient was found to be 0.9963. This method can also be applied to the assaying of glyoxylate.

Alcohol Oxidoreductases↗
PubMed2006

Phosphorylation of IRS1 at serine 307 and serine 312 in response to insulin in human adipocytes.

Feedback control in insulin signaling involves serine phosphorylation of insulin receptor substrate-1 (IRS1). By analyzing the insulin-induced phosphorylation of IRS1 at serine 307, serine 312, and tyrosine in the same primary human adipocytes, we now report that negative feedback phosphorylation of serine 312 (corresponding to murine serine 307) required relatively high concentrations of insulin (EC(50)=3 nM) for a long time (t(1/2) ca. 30 min) and reduced the steady-state tyrosine phosphorylation, without affecting the cellular concentration, of IRS1. In contrast, positive feedback phosphorylation of serine 307 was a rapid (t(1/2) ca. 2 min) event at physiological concentrations of insulin (EC(50)=0.2 nM).

Adipocytes↗