Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eleven studies of fetal serine fluxes were performed in chronically catheterized fetal lambs by continuous infusion of [1-13C]- and [U-14C]serine into a fetal brachial vein. At tracer serine steady state, samples were collected from the fetal abdominal aorta, umbilical vein, fetal hepatic vein, and fetal femoral vein and from the maternal femoral artery and uterine vein. Analyses were performed for plasma serine and glycine concentration, for serine and glycine 13C mole percent enrichment, and for whole blood 14CO2 and O2 concentrations. Uterine and umbilical blood flows were also measured. The placenta had a significant net uptake of fetal serine (2.1 +/- 0.5 mumol.min-1.kg-1, P < 0.01). Fetal plasma serine disposal rate (DR) was 42.5 +/- 3.9 mumol.min-1.kg-1.CO2 production from decarboxylation of fetal plasma serine represented 7.9 +/- 0.5% of DR, or 10.1 +/- 1.2 mumol CO2.min-1.kg-1. Fetal plasma glycine enrichment was 59.7 +/- 4.9% of fetal plasma serine enrichment. There was a significant loss of tracer serine from the fetal circulation into the placenta accounting for approximately 45% of infused tracer. Fifteen percent of this was converted to glycine and released into the umbilical circulation. There was a significant uptake of tracer serine by both fetal liver and fetal hindlimb with a significant CO2 production by both sites with serine oxidation predominantly in the carcass. These results indicate a high fetal serine disposal rate in the lamb, with rapid fetoplacental serine exchange, resulting in a net uptake of fetal serine by the placenta.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fetal serine fluxes across fetal liver, hindlimb, and placenta in late gestation. 141 1

Sphingomyelin (SPH) content and composition in different regions of the brain were analyzed in 2.5, 21.5 and 26.5-month-old rats. SPH content increased in the cerebral hemispheres, cerebellum and medulla oblongata plus pons as age increased. The highest SPH content was observed in 26.5-month-old rats, with values increasing by 1.74, 2.75 and 0.88-fold, respectively, over 2.5-month-old rats. The SPH fatty acid composition of brains from aged rats was markedly different from that of adult rats. Between 2.5 and 26.5 months of age the monoenoic/saturated fatty acid ratio increased from 0.22, 0.30 and 0.54 to 0.54, 0.68 and 1.03 in cerebral hemispheres, cerebellum and medulla oblongata plus pons, respectively. The percentage and content of fatty acids longer than 22 carbon atoms esterified to SPH increased with age from 18, 26 and 44 to 48, 52 and 62 mole % in cerebral hemispheres, cerebellum and medulla oblongata plus pons in 26.5-month-old rats. In subcortical white matter from aged rats, monoenoic 22-26 carbon atom fatty acids increased more than the saturated ones in 21.5-month-old rats relative to 2.5-month-old rats. In vitro synthesis of SPH from [3H]choline and [3H]palmitic acid in cerebral cortex and cerebellum showed no significant differences between adult rats and those 21.5 months of age. In cerebellum and in cerebral cortex, [14C]serine incorporation increased in aged rats. The results suggest that aging induces increases in both SPH content and in the monoenoic/saturated fatty acid ratio. These increases are quantitatively different in all brain regions analyzed.
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PMID:Effects of aging on the content, composition and synthesis of sphingomyelin in the central nervous system. 149 98

The mechanism of protein kinase C (PKC) activation by phosphatidyl-L-serine (PS) is highly specific and occurs with high cooperativity [Lee, M.-H., & Bell, R. M. (1989) J. Biol. Chem. 264, 14797-14805]. To further investigate the multiplicity and specificity of PS cofactor requirement, some of the PS molecules present in Triton X-100 mixed micelles were substituted with nonactivating phospholipids devoid of required amino or carboxyl functional groups. The ability of these phospholipids to spare or reduce the mole percent of PS required was determined. Addition of phosphatidyl-(3-hydroxypropionate) (PP) or phosphatidate (PA) reduced the mole percent of PS required for maximal activity from 10 to 4 mol %, and also reduced the cooperativity of activation with PS. In contrast, phosphatidylethanolamine did not alter the dependence on PS. Phosphatidylethanol (P-Et) reduced the PS requirement to 2-4 mol % and cooperatively less efficiently than PP or PA. Phosphatidylglycerol and phosphatidylinositol resemble P-Et in their ability to reduce PS requirements and cooperativity. Therefore, it appears that the ability of phospholipids to substitute for PS in PKC activation depends on the negative charge in the phospholipid head group and the efficiency of substitution appears to be directly related to the negative charge density. The presence of two acyl groups within the phospholipid cofactor proved important since lyso-PS and lyso-PA replaced a portion of PS molecules required less efficiently than P-Et. Sodium oleate and sodium dodecyl sulfate behaved like lyso-PS. When other anionic lipids are present, approximately four molecules of PS per micelle are required for maximal PKC activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Supplementation of the phosphatidyl-L-serine requirement of protein kinase C with nonactivating phospholipids. 160 42

A protease inhibitor specific to trypsin and chymotrypsin was purified from horsegram (Dolichos biflorus) with the inhibition index 0.24 micrograms/micrograms for trypsin and 0.36 micrograms/micrograms for chymotrypsin. In SDS-PAGE, the inhibitor protein was seen as a single band with apparent molecular mass Mr = 15,500. However, on fast protein liquid chromatography (FPLC) or non-denaturating PAGE, the inhibitor resolved into four components revealing the existence of isoinhibitors. Data on amino acid analysis indicate that the isoinhibitors are closely related. The major amino acids in the inhibitor are half cystine (18.9 mole %), aspartic acid (12.7 mole %) and serine (14.3 mole %). The inhibitor was partially stable to 0.1% sodium dodecyl sulphate, 8M urea or 6M guanidine hydrochloride. The inhibitory activity was lost on reduction or carboxamidomethylation or acetylation. Modification of the arginine groups or CNBr cleavage of the protein did not result in significant loss of either tryptic or chymotryptic inhibitory activities. The isoinhibitors separated by FPLC reacted with polyclonal antibody raised in rabbits and had pI values ranging from 4.8-5.1. The horsegram inhibitor thus resembles other Bowman-Birk protease inhibitors.
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PMID:Nature of the tryptic/chymotryptic inhibitor from horsegram (Dolichos biflorus). 181 76

Serine 130 is one of seven residues that form a total of seven hydrogen bonds with the sulfate completely sequestered deep in the cleft between the two lobes of the bilobate sulfate-binding protein from Salmonella typhimurium. This residue has been replaced with Cys, Ala, and Gly by site-directed mutagenesis in an Escherichia coli expression system. Replacement with the isosteric Cys caused a 3200-fold decrease in the sulfate-binding activity relative to the wild-type activity, whereas replacement with Ala and Gly resulted in only 100- and 15-fold decreases, respectively. The effect of the Cys substitution is attributed largely to steric effect, whereas the Gly substitution more nearly reflects the loss of one hydrogen bond to the bound sulfate with a strength of only 1.6 kilocalories per mole.
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PMID:A nonconservative serine to cysteine mutation in the sulfate-binding protein, a transport receptor. 190 Sep 53

Incubation of tryptophanyl-tRNA synthetase from bovine pancrease with [gamma-32P]ATP of [gamma-32P]GTP and casein kinase II from rabbit liver leads to the incorporation of labeled phosphate into serine residues of synthetase polypeptide. The maximal level of 32P incorporation into synthetase polypeptide (Mr = 60 kDa) 0.15 moles of 32P per 1 mole of polypeptide was observed. Electrophoretic analysis according to O'Farrell showed that kinase phosphorylates exclusively the most acidic polypeptides (pI 4.9) of the synthetase preparation. Pretreatment of synthetase with animal acidic and alkaline phosphatases had no influence on the level of 32P incorporation in synthetase during subsequent incubation in the presence of casein kinase II.
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PMID:[Phosphorylation of tryptophanyl-tRNA-synthetase by casein kinase type II]. 209 10

Casein kinase II from bovine brain transfers about one mole of phosphate to a serine residue near the COOH terminus of the heavy chain of myosin isolated from bovine brain. We have purified and characterized a peptide that contains this phosphoserine. The peptide was generated by chymotryptic and thermolytic digestion and was isolated by gel filtration, Fe3+ affinity chromatography, and reverse-phase high pressure liquid chromatography. Its sequence, Leu-Glu-Leu-Ser(PO4)-Asp-Asp-Asp-Asp-Glu-Ser-Lys-Ala-Ser-(Xaa)-Ile-Asn-Glu-Thr- Gln-Pro-Pro-Gln, shows that the Ser(PO4) is in an acidic environment, as is typical for casein kinase II phosphorylation sites. The "hydrophobic repeat" typical of alpha-helical coiled-coils is absent, suggesting that the sequence is part of a non-helical "tail piece" of the heavy chain. A synthetic peptide corresponding to residues 1-9 is shown to be an effective substrate for casein kinase II.
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PMID:Amino acid sequence around the serine phosphorylated by casein kinase II in brain myosin heavy chain. 210 26

Muscarinic acetylcholine receptors purified from porcine cerebrum were phosphorylated by protein kinase C purified from the same tissue. More than 1 mol of phosphate was incorporated per mole of receptor, with both serine and threonine residues being phosphorylated. Neither the degree nor the rate of the phosphorylation was affected by the presence or absence of acetylcholine. GTP-sensitive high-affinity binding with acetylcholine was observed for muscarinic receptors reconstituted with GTP-binding proteins (Gi or Go), irrespective of whether muscarinic receptors or the GTP-binding proteins had been phosphorylated by protein kinase C or not. This indicates that the interaction between purified muscarinic receptors and purified GTP-binding proteins in vitro is not affected by their phosphorylation.
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PMID:Phosphorylation by protein kinase C of the muscarinic acetylcholine receptor. 210 45

Cyclic AMP-dependent phosphorylation of the rat brain sodium channel was reported to be restricted to five sites within an approximately 210 amino acid region of the primary sequence that is deleted in the homologous sodium channel from rat skeletal muscle. We find that, in spite of this deletion, the rat muscle sodium channel alpha-subunit is also an excellent substrate for phosphorylation by this kinase both in primary muscle cells in tissue culture and in vitro after isolation from adult muscle. Sodium channel protein purified from adult rat skeletal muscle was readily phosphorylated in vitro by the catalytic subunit of the bovine cyclic AMP-dependent protein kinase (PKa). Only the 260,000 MW alpha-subunit was labeled, with a maximum level of incorporation in vitro of approximately 0.5 mol [32P]phosphate per mole of channel protein. The beta-subunit of the channel is not phosphorylated under these conditions. In primary rat skeletal muscle cells in culture, incorporation of phosphate into the channel alpha-subunit is stimulated 1.3- to 1.5-fold by treatment of the cells with forskolin. Phosphorylation of the sodium channel isolated from these cells could also be demonstrated in vitro using PKa. This in vitro phosphorylation could be inhibited 80-90% by pretreatment of the cells in culture with forskolin, suggesting that the sites labeled in vitro by PKa were the same as those phosphorylated in the intact cells by the endogenous cyclic AMP-dependent kinase. In both the adult muscle channel and the channel from muscle cells in culture, phosphorylation by PKa was limited to serine residues.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Phosphorylation of the rat skeletal muscle sodium channel by cyclic AMP-dependent protein kinase. 215 54

An inositol 1,4,5-trisphosphate 3-kinase purified from human platelets contains two major components, 53 and 36 kDa polypeptides. Each polypeptide expresses Ca2+/calmodulin-dependent enzymatic activity and is phosphorylated by an unidentified protein kinase in the enzyme preparation. The 36-kDa polypeptide may be further phosphorylated on serine residues by protein kinase C to a stoichiometry of 0.8 mole phosphate per mole of protein. Phosphorylation of the 36-kDa component is correlated with inhibition of the kinase activity; the inhibitory effect is dependent upon Ca2+ and phosphatidylserine/diolein and may be blocked by a selective peptide inhibitor of protein kinase C. Phosphorylation by protein kinase C decreases the Vmax of the enzyme from 160 to 28 nmol/mg/min; the Km (0.76 microM) is not altered. These data suggest that protein kinase C may negatively regulate inositol 1,4,5-trisphosphate 3-kinase activity in the human platelet.
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PMID:Phosphorylation by protein kinase C inactivates an inositol 1,4,5-trisphosphate 3-kinase purified from human platelets. 216 76


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