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)

Response of the fetal kidney to metabolic acidosis was studied in five fetal lambs, 115-125 days gestation, in order to evaluate the renal contribution to elimination of hydrogen ion during intra-uterine development. Experiments were conducted on healthy unanesthetized fetuses, intact in utero, with catheters implanted at hysterotomy into a fetal femoral artery and vein and into the bladder via the urachus, four or more days prior to the study. A metabolic acidosis was induced by infusion of isotonic lactic acid, 15 m mole/kg, intravenously over a period of 90 minutes. Serial arterial samples were taken and urine collected in fractions before, during and for three hours following the infusion, for measurements of pH, bicarbonate, lactate and electrolytes as well as urine output. During the infusion, urine pH fell from 6.65 to 6.25 and was 6.34 three hours later (Figs. 1 to 4, Tabs. III to IV). Lactic acid infusion caused a prompt increase in urine output from a mean rate of 0.12 to a maximum of 0.28 ml/kg/min at the end of the infusion, returning to control rates three hours later. Lactate excretion increased from 0.05 to a maximum of 4.6 mumole/kg/min at the end of infusion; titratable acid increased from 0.22 to a maximum of 4 muEq/kg/min; the rates of excretion of lactate and titratable acid were still higher than control at the end of three hours. Ammonia excretion increased from 0.21 to a maximum of 0.56 muEq/kg/min three hours after the end of infusion. The acid infusion caused a small but significant fall in excretion of bicarbonate. During the 90 minutes of infusion and over the following three hours, about 800 mumole lactate was excreted while net acid excretion over the same period was no more than half that amount. The diuresis was also accompanied by a net loss of sodium and chloride, the excretion of these ions increasing more than threefold following acid infusion; excretion of potassium decreased to one-third its rate prior to the infusion. During the 90 minutes of infusion, blood pH fell from 7.36 to 7.13, base deficit rose from 3.8 to 16.4 mEq/L and lactate rose from 2.2 to 14.8 mM/L; there was also a small but significant rise in both blood PCO2 and PO2 (Figs. 1 to 2, Tabs. I to II). During the following three hours of recovery, pH rose gradually to 7.29, base deficit and lactate fell to 7.4 mEq/L and 8.7 mM/L respectively. Since renal excretion of net acid and lactate was small, the decrease in blood base deficit and lactate levels during the recovery must therefore be mainly due to equilibration in various fetal compartments as well as placental transfer. These experiments indicate that, in the lamb fetus, intact in utero, the kidney although limited by immaturity of several mechanisms, is capable of responding to an acid load and thus can make a small contribution to fetal homeostasis. The increase in excretion of net acid is accompanied by loss of sodium and chloride in the urine.
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PMID:Renal response to acid loading in the developing lamb fetus, intact in utero. 0 Apr 79

The membrane penicillinase of Bacillus licheniformis 749/C has been demonstrated to be a phospholipoprotein. The homogeneous enzyme gives a positive reaction for phosphorous and for unsaturated fatty acids, has a molecular weight of 33,000 in contrast to 29,000 for the exoenzyme, and contains 8 to 9 additional residues of aspartate or asparagine, 4 to 5 of serine, 7 of glutamate or glutamine, and 4 to 5 of glycine per mole. The COOH-terminal sequence of both membrane and exoenzymes is -Met-Asn-Gln-Lys-COOH; hence the extra peptide portion present in the membrane enzyme is not attached to the COOH-terminus of the exoenzyme. Procedures which readily detected the lysine residue at the NH2 terminus of the exoenzyme did not yield a positive test with the membrane form. The NH2 terminus of the membrane enzyme may be blocked by or linked to the phospholipid. A procedure for the preparation of membrane penicillinase on a large scale and an improved method for purification of the exoenzyme have been developed.
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PMID:Purification of plasma membrane penicillinase from Bacillus licheniformis 749/C and comparison with exoenzyme. 0 71

The amide content of neocarzinostatin (NCS), an antitumor protein, has been determined by analysing asparagine and glutamine in the Pronase-aminopeptidase M digests of tetra-S-carboxymethyl-NCS and carboxyl-modified NCS (modified with a water-soluble carbodiimide and [14C]glycine methyl ester). Preneocarzinostatin (PRE) was separated and purified from a crude NCS preparation by CM-cellulose column chromatography. PRE was found to contain one mole less asparagine than NCS, and asparagine was deamidated to aspartic acid in PRE. A time-dependent conversion of NCS to PRE at pH 3.2 at 4 degrees or in 0.1 M acetic acid at 26 degrees was studied in two ways; first, by quantitative determination of NCS and PRE by CM-cellulose column chromatography and second, by following the release of free NH3 during dialysis in an air-tight container. Within experimental error, PRE was indistinguishable from NCS in amino acid content after acid hydrolysis, as well as in apparent molecular weight as determined by SDS-disc gel electrophoresis (10% acrylamide), and N- and C-terminal amino acid residues. Both NCS and PRE shared a common antigenicity as determined by Ouchterlony's agar diffusion method. Only a slight difference between the two in electrophoresis on a cellulose acetate membrane and on a peptide map of the tryptic digest was demonstrated. PRE, however, was completely devoid of biological activity. In addition to the chromatographic difference, a conformational difference was observed by CD spectroscopy, namely, an apparently looser structure of PRE was indicated by the shallowness of the trough in the 240-265 nm region. This interpretation was supported by the finding that digestions by Pronase were more extensive with PRE than with NCS. These results indicate an important role of the single asparagine residue (Asn 83) of NCS in the biological activity, which is evidently governed by the conformation.
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PMID:Spontaneous deamidation of a protein antibiotic, neocarzinostatin, at weakly acidic pH. Conversion to a homologous inactive preneocarzinostatin due to change of asparagine 83 to aspartic acid 83 accompanied by conformational and biological alterations. 1 34

Angiotensin-converting enzyme has been solubilized from a particulate fraction of rabbit lung and purified to apparent homogeneity in 11% yield by a procedure including fractionation with DEAE-cellulose and calcium phosphate gel, elution from Sephadex G-200, and lectin affinity chromatography. The molecular weight estimated by equilibrium sedimentation was approximately 129,000, either in the absence or presence of 6 M guanidine hydrochloride. A slightly higher value of 140,000 determined for the reduced, denatured protein by gel electrophoresis in the presence of sodium dodecyl sulfate and a much higher figure derived from gel filtration are probably due to the glycoprotein nature of the enzyme. Its oligosaccharide content accounted for 26% of the weight calculated from its amino acid and carbohydrate composition. The estimated content of sugar residues per mole was: galactose, 57; N-acetylglucosamine, 53; mannose, 43; N-acetylneuraminic acid, 19; and fucose, 4. Threonine and alanine were identified, respectively, as NH2-terminal and COOH-terminal residues by the dansylation procedure and by digestion with carboxypeptidase A. The enzyme was found to contain approximately 1 g atom of zinc per mol. Km values for hydrolysis of hippurylhistidylleucine and angiotensin I were 2.3 and 0.07 mM, and the corresponding turnover numbers were 15,430 and 792 mol/min/mol at 37 degrees. Bradykinin was also a substrate, and release of its COOH-terminal dipeptide, Phe-Arg, was catalyzed at a comparable rate to that of His-Leu from the COOH terminus of angiotensin I. Enzyme activity required the presence of chloride ions and was inhibited by EDTA and by low concentrations of Bothrops bradykinin-potentiating peptides. In addition, hydrolysis of hippurylhistidylleucine was inhibited competitively by other defined peptides, including di- and tripeptides, which were not substrates.
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PMID:Pulmonary angiotensin-converting enzyme. Structural and catalytic properties. 16 57

The new bifunctional reagent, N-(4-chloromercuriphenyl)-4-chloro-3,5-dinitrobenzamide (I) was used to investigate the quaternary structure of yeast alcohol dehydrogenase. The four essential - SH groups of the enzyme were substituted by the mercuriphenyl moiety of compound I in the course of the reaction of one mole of protein with four moles of the reagent (one molecule of compound I incorporated by yeast alcohol dehydrogenase monomer). In a second step only two of the four chlorodinitrophenyl fragments bound to the protein established intermonomeric cross-links with non-essential - NH2 groups. The resulting dimers could be re-dissociated with mercaptoethanol. This result suggests that the four protomers of the enzyme could be arranged as a dimer of dimers.
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PMID:New protein reagents. N-(4-Chloromercuriphenyl)-4-chloro-3,5-dinitrobenzamide and its use as a probe of the quaternary structure of yeast alcohol dehydrogenase. 19 5

Equal mole doses of the anions of disodium carbamyl phosphate (carbamyl P) or sodium cyanate, antisickling agents, have been compared in C57B1 mice. Using 15 mice per group, two groups were given the equivalent ip dose of carbamyl P or cyanate anion (7 mmoles/kg/day) in a divided dose, in the morning and six hours later, for 17--18 days. The control group received sodium chloride (13.8 mmoles of Na+ or Cl-/kg/day). Surviving mice per group were sodium chloride, 15/15; disodium carbamyl P, 14/15; and sodium cyanate, 0/15, all mice died by day 2. Surviving mice appeared normal throughout the study, and no abnormalities were seen at necropsy. The hematologic measurements were the same for sodium chloride or disodium carbamyl P, including hemoglobin, packed cell volume, erythrocyte counts, leucocyte counts, and differential counts. The mean hemoglobin carbamylation was 1.24 (+/- 0.06 SE) moles of valine hydantoin/mole of hemoglobin tetramer in mice receiving disodium carbamyl P for 18 days, sufficient for antisickling activity. The enzymatic degradation of carbamyl P to NH3, CO2, and Pi was measured in serial blood samples in additional C57B1 and DBA/2J mice following ip injections of carbamyl P or cyanate. Both NH3 and Pi increased immediately after giving carbamyl P, but no increase occurred after cyanate administration. Thus enzymatic degradation of carbamyl P occurs in vivo and appears to be an important detoxification mechanism. When equivalent mole doses of anion are administered, disodium carbamyl P is less toxic than sodium cyanate in mice.
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PMID:Antisickling agents: effects of carbamyl phosphate or cyanate on survival, erythrocytes, and leucocytes in the mouse. 53 3

Several lines of evidence indicate that ligandin consists of two different subunits. The protein dissociates into two components that are detected by electrophoresis in a discontinuous sodium dodecyl sulfate system, or in acid-urea gels, and by isoelectric focusing in the presence of urea. The apparent molecular weights of the two polypeptides are 25,000 and 22,000. Alkylated or succinylated ligandins also exhibit subunit heterogeneity and resolved into two bands in these electrophoretic systems. Cross-linked ligandin showed only one band in sodium dodecyl sulfate-gel electrophoresis indicating that the two subunits are part of a heterodimeric protein rather than monomers of two different proteins. No dansylated terminal amino acids were detected suggesting that the NH2-terminal residues of both chains are blocked. One mole of arginine or phenylalanine was released per mole of ligandin after digestion with carboxypeptidase B or A, respectively. Tryptic maps of succinylated ligandin were consistent with identical disposition of arginine residues in both chains, but several additional tryptic peptides were obtained with native ligandin as compared to the predicted number if both subunits were identical. These observations are consistent with the possibility that both subunits contain common sequences and that a small peptide of about 25 to 30 amino acid residues is cleaved from the COOH-terminal of the larger subunit to produce the smaller subunit.
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PMID:Studies on subunit structure and evidence that ligandin is a heterodimer. 66 96

An acidic protein, extractable in neutral salt solutions from rat skin, was markedly enriched when precipitated by dialysis against 0.5 M acetic acid. After dissolving the precipitate in 0.5 M Tris-HCl buffer, pH 8.0, the protein was disaggregated by the addition of the nonionic detergent Triton X-100 and purified by chromatography on Sephadex G-100 and DEAE-Sephadex A-50 columns. The protein isolated under nondenaturing conditions appeared to be essentially homogeneous by its migration as a single band on (a) cellulose acetate membrane electrophoresis at pH 8.6; (B) 4% and 7.5% polyacrylamide gel electrophoresis at ph 8.9; (C) sodium dodecyl sulfate (10%) polyacrylamide gel electrophoresis at pH 7.0; and by (d) its complete freedom from collagen, the major contaminating protein. The molecular weight of the protein was determined as 76,000 +/- 2,000 from its electrophoretic mobility in sodium dodecyl sulfate polyacrylamide gels and 75,000 from its elution volume in Sephadex G-100 columns. Reduction and alkylation of the protein failed to generate smaller subunits. The amino acid composition of the protein showed that it was relatively rich in glutamic and aspartic acids, which together comprised 25% of its total residues. Hydrophobic amino acids like phenylalanine, leucine, isoleucine, valine, methionine, alanine, proline, and cystine accounted for about 34% of the total residues in the protein. No free NH2-terminal amino acid could be detected in the purified protein by the dansylation method. Each mole of protein contained 11 mol of phosphate. Triton X-100 was necessary for achieving nondestructive disaggregation of the acidic protein. Each mole of protein bound about 3200 mol of Triton X-100 or 10 mol of Congo red. While the detergent binding could be reversed by dialysis, Congo red formed a stable complex with the protein.
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PMID:Purification and properties of an acidic protein from rat skin. 81 54

A low molecular weight protein found in the soluble extract of bovine adrenal medulla, and having a high affinity for calcium ions has been purified to apparent homogeneity. The purification requires three steps, including ammonium sulfate fractionation, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sephadex G-100. The protein was homogeneous by the criteria of both standard and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, sedimentation velocity analysis, and NH2-terminal analysis. The calcium-binding protein is very acidic and has an isoelectric point of 4.27. Aspartic and glutamic acid together account for 30% of the total amino acid composition. The ultraviolet absorption spectrum reveals a A280/A260 ratio of 0.83 and shows discrete maxima at 258, 264, 269, 278, and 284 nm. Two moles of calcium are bound per mole of protein. The apparent Kp is approximately 20 muM. The molecular weight was found to be 16,000 +/- 1,000 by both sodium dodecyl sulfate gel electrophoresis and sedimentation equilibrium ultracentrifugation. The protein was found to consist of a single polypeptide chain by the criteria of tryptic peptide mapping and NH2-terminal analysis. Amino acid analysis revealed the absence of tryptophan, single residues of cysteine and histidine, and 2 residues of tyrosine. The protein was void of carbohydrate and phosphate. The structural similarities and possible functional correlation between adrenal medulla calcium-binding protein and troponin-C from muscle tissue are discussed.
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PMID:Purification and characterization of a troponin-C-like protein from bovine adrenal medulla. 81 60

Five proteinase inhibitors which all inhibit the activity of bovine trypsin [EC 3.4.21.4] were isolated from African Elapid venoms of Hemachatus haemachatus (HHV, Ringhal's cobra) and Naja nivea (NNV, Cape cobra). All the inhibitors were essentially homogeneous by polyacrylamide gel electrophoresis in the presence or absence of sodium dodecylsulfate. Amino acid analysis and terminal analysis also supported their chemical homogeneities, except for one of the two inhibitors from Hemachatus haemachatus venom. The isolated inhibitors had a molecular weight of about 6,500, consisting of 52 to 57 amino acid residues, and they were all devoid of tryptophan. However, their amino acid compositions differed from each other. One of the three inhibitors isolated from Naja nivea venom, designated NNV inhibitor Ia, was unique, in that 4 half-cystinyl residues per mole fof the polypeptide were present, whereas all the others contained six residues. Of the isolated proteinase inhibitors, the complete amino acid sequences of two major inhibitors were established by manual and automatic Edman degradations and standard enzymatic techniques. Each of the inhibitors, designated HHV inhibitor II and NNV inhibitor II, consisted of 57 amino acid with arginine and glycine at the NH2- and COOH-termini, respectively. Both contained six half-cystines in disulfide linkages, and their overall amino acid sequences were similar, showing 91% homology. The two inhibitors differed in sequence by only five amino acid replacements, Asp-3 to Arg; Tyr-17 to Arg; Leu-25 to Arg; Gln-32 to Glu; and Arg-52 to His, in the 57 residue peptide chain. Comparing the amino acid sequences of these two cobra venom inhibitors with those of Russell's viper venom inhibitor II and bovine pancreatic trypsin inhibitor (BPTI), about 50% homology was found in their sequences. The 6 half-cystinyl residues of these inhibitors were in the same linear positions. Moreover, the regions which are structurally and functionally important in the well-known BPTI molecule were found with extremely high sequence homology in the cobra venom inhibitors. These findings strongly suggest that the cobra venom inhibitors as well as Russell's viper inhibitor II have very similar conformations to that established for BPTI.
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PMID:Snake venom proteinase inhibitors. III. Isolation of five polypeptide inhibitors from the venoms of Hemachatus haemachatus (Ringhal's corbra) and Naja nivea (Cape cobra) and the complete amino acid sequences of two of them. 95 Mar 37


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