351
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Ali S, Iqbal M, Yaqub M. Surma--a toxic cosmetic? J PAK MED ASSOC 1988; 38:281-2. [PMID: 3144612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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352
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Iqbal M, Rasool MI, Safdar S, Sohail S. Anal eroticism: self introduced foreign bodies in the rectum. J PAK MED ASSOC 1988; 38:223-4. [PMID: 3149316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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353
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Malik IA, Ahmed A, Iqbal M, Legters LJ, Luqman M, Akhtar MA. Infection with delta agent in Pakistan. Introduction of a new hepatitis agent. J PAK MED ASSOC 1988; 38:126-8. [PMID: 3146653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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354
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Iqbal M, Verrall RE. Implications of protein folding. Additivity schemes for volumes and compressibilities. J Biol Chem 1988; 263:4159-65. [PMID: 3346243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Partial specific volume and compressibility properties of the extended state of proteins are estimated from additivity schemes using revised amino acid and peptide data. These calculated properties are compared with the experimental data of the native state in order to assess the contribution from folding. Results of this treatment show that, in the case of partial specific volumes, there is close agreement between the two data sets for a number of proteins. The implication is that subtle compensatory contributions in volume occur during the folding process. In the case of compressibilities, however, a substantial difference is observed which is believed to arise because of the hydrophobic interior created in the native protein as a result of the folding process. Using suitable measures of protein hydrophobicities and estimates of the fraction of buried apolar residues, a "micellar model of protein compressibility" is proposed and tested for several proteins. Results obtained from this model show good agreement with the experimental data for the native state of a number of proteins.
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355
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Anantharamaiah GM, Hughes TA, Iqbal M, Gawish A, Neame PJ, Medley MF, Segrest JP. Effect of oxidation on the properties of apolipoproteins A-I and A-II. J Lipid Res 1988. [DOI: 10.1016/s0022-2275(20)38529-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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356
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Anantharamaiah GM, Hughes TA, Iqbal M, Gawish A, Neame PJ, Medley MF, Segrest JP. Effect of oxidation on the properties of apolipoproteins A-I and A-II. J Lipid Res 1988; 29:309-18. [PMID: 3132519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purified apolipoprotein A-I has been separated by reversed-phase high performance liquid chromatography (HPLC) into multiple peaks and these peaks have been characterized. One peak, apoA-Ib had a relatively longer retention time on HPLC but its retention time could be shortened by treatment by hydrogen peroxide. CNBr cleavage studies indicated that the differences in apoA-Ib and in its oxidation product, apoA-Ia, were due to the different oxidation states of methionine. This phenomenon was also observed in apoA-II, where methionine oxidation produced two more forms of this apolipoprotein in addition to the native form. These isomers were found to have different secondary structures and affinities for lipid. Model peptide analogs of the amphipathic helix with the same sequence but with methionine and methionine sulfoxide at the nonpolar face of the amphipathic helix were synthesized and studied. It was found that the lipid affinities of these synthetic peptide isomers were very different. They also differed in their secondary structures as studied by circular dichroism (CD). We propose that methionine oxidation introduces hydrophilic residues at the nonpolar face of the amphipathic helical domains of these apolipoproteins and, therefore, alters their secondary structure and lipid affinity.
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357
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358
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Epand RM, Gawish A, Iqbal M, Gupta KB, Chen CH, Segrest JP, Anantharamaiah GM. Studies of synthetic peptide analogs of the amphipathic helix. Effect of charge distribution, hydrophobicity, and secondary structure on lipid association and lecithin:cholesterol acyltransferase activation. J Biol Chem 1987; 262:9389-96. [PMID: 3597415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Four peptides capable of forming an amphipathic alpha-helix have been synthesized and their conformational and lipid-binding properties studied. These peptides have been designed to vary the alpha-helix-forming potential as well as the charge distribution of the model peptide. The resulting peptide analogs and their complexes with dimyristoyl phosphatidylcholine were studied by using right angle light scattering, negative stain electron microscopy, nondenaturing gradient gel electrophoresis, circular dichroism, intrinsic tryptophan fluorescence, and differential scanning calorimetry techniques. The four analogs, [Glu4,9, Leu11,17] (reverse-18A, [Glu4,9, Leu5,11,17] reverse-18A, [Glu1,8, Leu11,17] 18A, and [Glu1,8, Leu5,11,17] 18A were derived from a model amphipathic peptide Asp-Trp-Leu-Lys-Ala-Phe-Tyr-Asp-Lys-Val-Ala-Glu-Lys-Leu-Lys-Glu-Ala-Phe (18A) whose lipid-associating properties strongly mimic apolipoprotein A-I or derived from Lys-Trp-Leu-Asp-Ala-Phe-Tyr-Lys-Asp-Val-Ala-Lys-Glu-Leu-Glu-Lys-Ala-Phe (reverse-18A), a peptide with little affinity for lipid and having a reversed charge distribution compared to the 18A peptide. We have shown that by substituting glutamic acid and leucine for aspartic acid and alanine, respectively, in a weak lipid-associating amphipathic helix peptide, the lipid-associating ability can be increased. Thus, peptides with both kinds of charge distribution can associate with the lipid. The ability of the peptide to disrupt phospholipid bilayers, however, is higher for 18A analogs compared to the reverse-18A analogs even after increasing the helix-forming potential and hydrophobicity. In addition to forming smaller lipoprotein particles, the modified 18A analogs were much superior to the modified reverse-18A analogs in their ability to activate the enzyme lecithin:cholesterol acyltransferase. This demonstrates that the positions of charged residues in the amphipathic helix play an important role in lecithin:cholesterol acyltransferase activation.
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359
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Urry DW, Trapane TL, Iqbal M, Venkatachalam CM, Prasad KU. Carbon-13 NMR relaxation studies demonstrate an inverse temperature transition in the elastin polypentapeptide. Biochemistry 1985; 24:5182-9. [PMID: 4074687 DOI: 10.1021/bi00340a034] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Carbon-13 NMR longitudinal relaxation time and line-width studies are reported on the coacervate concentration (about 60% water by weight) of singly carbonyl carbon enriched polypentapeptides of elastin: specifically, (L-Val1-L-[1-13C]Pro2-Gly3-L-Val4-Gly5)n and (L-Val1-L-Pro2-Gly3-L-Val4-[1-13C]Gly5)n. On raising the temperature from 10 to 25 degrees C and from 40 to 70 degrees C, carbonyl mobility increases, but over the temperature interval from 25 to 40 degrees C, the mobility decreases. The results characterize an inverse temperature transition in the most fundamental sense of temperature being a measure of molecular motion. This transition in the state of the polypentapeptide indicates an increase in order of polypeptide on raising the temperature from 25 degrees C to physiological temperature. This fundamental NMR characterization corresponds with the results of numerous other physical methods, e.g., circular dichroism, dielectric relaxation, and electron microscopy, that correspondingly indicate an increase in order of the polypentapeptide both intramolecularly and intermolecularly for the same temperature increase from 25 to 40 degrees C. Significantly with respect to elastomeric function, thermoelasticity studies on gamma-irradiation cross-linked polypentapeptide coacervate show a dramatic increase in elastomeric force over the same interval that is here characterized by NMR as an inverse temperature transition. The temperature dependence of mobility above 40 degrees C indicates an activation energy of the order of 1.2 kcal/mol, which is the magnitude of barrier expected for elasticity.
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360
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Lee C, Iqbal M, Gill U, Sutherland R. Ligand exchange reactions with η6-arene-η5-cyclopentadienyliron cations under thermal or photochemical conditions. J Organomet Chem 1985. [DOI: 10.1016/0022-328x(85)80107-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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361
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Johnson BC, Yilgör İ, Tran C, Iqbal M, Wightman JP, Lloyd DR, McGrath JE. Synthesis and characterization of sulfonated poly(acrylene ether sulfones). ACTA ACUST UNITED AC 1984. [DOI: 10.1002/pol.1984.170220320] [Citation(s) in RCA: 140] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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362
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Iqbal M, Balaram P, Showell HJ, Freer RJ, Becker EL. Conformationally constrained chemotactic peptide analogs of high biological activity. FEBS Lett 1984; 165:171-4. [PMID: 6692914 DOI: 10.1016/0014-5793(84)80163-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The stereochemically constrained chemotactic peptide analogs, formylmethionyl-alpha-aminoisobutyryl-phenylalanine (formyl-Met-Aib-Phe-OH) and formylmethionylcycloleucinylphenylalanine (formyl-Met-Cyl-Phe-OH) are highly effective in inducing lysosomal enzyme release from rabbit neutrophils. NMR studies of the Aib2 analog in (CD3)2SO favor a folded conformation in which the Phe NH group is inaccessible to solvent. Intramolecularly hydrogen-bonded conformations involving a Met-Aib-beta-turn or a gamma-turn centered at Aib2 are considered. The results suggest that folded conformations may allow highly active interactions with the neutrophil formylpeptide receptor.
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363
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Rawat JP, Iqbal M, Chitra. Ligand exchange separation of phenols on alumina in Fe(III) form. Chromatographia 1983. [DOI: 10.1007/bf02259325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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364
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Francis AK, Iqbal M, Balaram P, Vijayan M. Crystal structure of Boc-Ala-Aib-Ala-Aib-Aib-methyl ester, a pentapeptide fragment of the channel-forming ionophore suzukacillin. Biopolymers 1983. [DOI: 10.1002/bip.360220606] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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365
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Iqbal M, Balaram P. The helical conformations of 14- and 16-residue fragments of suzukacillin, a membrane channel-forming polypeptide. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 706:179-87. [PMID: 7126598 DOI: 10.1016/0167-4838(82)90485-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The suzukacillin fragments, Boc-Ala-Aib-Aib-Gln-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (14), Boc-Ala-Aib-Ala-Aib-Aib-Gln-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (16G) and the completely apolar 16-residue peptide in which the glutamine residue has been replaced by alanine (16A) have been studied by 270 MHz 1H-HMR, in C2HCl3 and (C2H3)2SO solution. Intramolecularly hydrogen-bonded NH groups have been identified by temperature and solvent dependence of chemical shifts. Peptides 14 and 16A adopt folded 3(1)) helical conformations stabilized by 11 and 13 hydrogen bonds, respectively. In peptide 16G there are 12 intramolecular hydrogen bonds, with the glycine NH being solvent-exposed, in contrast to 14 and 16A.
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366
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Iqbal M, Balaram P. Aggregation of apolar peptides in organic solvents. Concentration dependence of1H-nmr parameters for peptide NH groups in 310 helical decapeptide fragment of suzukacillin. Biopolymers 1982. [DOI: 10.1002/bip.360210711] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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367
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Francis AK, Pulla Rao C, Iqbal M, Nagaraj R, Vijayan M, Balaram P. Helical conformations of three crystalline pentapeptide fragments of suzukacillin, a membrane channel forming polypeptide. Biochem Biophys Res Commun 1982; 106:1240-7. [PMID: 7115398 DOI: 10.1016/0006-291x(82)91245-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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368
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Iqbal M, Balaram P. Membrane channel forming polypeptides. 270-MHz proton magnetic resonance studies of the aggregation of the 11-21 fragment of suzukacillin in organic solvents. Biochemistry 1981; 20:7278-84. [PMID: 6274396 DOI: 10.1021/bi00528a035] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
270-MHz 1H NMR studies of the 11-21 suzukacillin fragment Boc-Gln-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (11-G) and its analogue Boc-Ala-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (11-A) have been carried out in CDCl3 and (CD3)2SO. The NH chemical shifts and their temperature coefficients have been measured as a function of peptide concentration in both solvents. It is established that replacement of Gln by Ala is without effect on backbone conformation. Both peptides adopt highly folded 310 helical conformations stabilized by seven intramolecular 4 leads to hydrogen bonds. Nonlinear temperature dependences are demonstrated for free NH groups in the Gln(1) peptide. Aggregation is mediated by intermolecular hydrogen bonds formed by solvent-exposed NH groups. A major role for the Gln side chain in peptide association is suggested by differences in the NMR behavior of the Gln(1) and Ala(1) peptides. For the Gln(1) peptide in CDCl3, the carboxamide side chain carbonyl group forms an intramolecular hydrogen bond to the peptide backbone, while the trans side chain NH shows evidence for intermolecular interactions. In (CD3)2SO, the cis carboxamide NH is involved in intermolecular hydrogen bonding. The possible role of the central Gln residue in stabilizing aggregates of peptide channel formers is discussed, and a model for hexameric association is postulated.
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369
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Iqbal M, Balaram P. Membrane channel forming polypeptides. 270-MHz hydrogen-1 nuclear magnetic resonance studies on the conformation of the 11-21 fragment of suzukacillin. Biochemistry 1981; 20:4866-71. [PMID: 7295656 DOI: 10.1021/bi00520a010] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
270-MHz 1H NMR studies on the synthetic suzukacillin fragments Boc-Leu-Aib-Gly-Leu-Aib-OMe (13-17), Boc-Gln-Aib-Leu-Aib-Gly-Leu-Aib-OBz (11 -17), Boc-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (13-21), and Boc-Gln-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (11-21) have been carried out in CDCl3 and (CD3)2SO. The intramolecularly hydrogen-bonded amide hydrogens in these peptides have been identified by using solvent titration experiments and temperature coefficients of NH chemical shifts in (CD3)2SO. The peptides are shown to favor conformations stabilized by intramolecular 4 leads to 1 hydrogen bonds. The 11-21 fragment adopts a highly folded, largely 310 helical conformation stabilized by seven intramolecular hydrogen bonds. An eighth NH group [Gly(5)] appears to be involved in a weaker interaction. Evidence for the possible participation of the Gln side-chain carboxamide group in hydrogen bonding to the peptide backbone is also presented.
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370
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Iqbal M, Nagaraj R, Balaram P. 1H N.M.R. studies of protected alpha-aminoisobutyric acid containing peptides. Chemical shift nonequivalence of benzyloxycarbonyl methylene protons. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1981; 18:208-13. [PMID: 6273348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The benzylic methylene protons in a large number of benzyloxycarbonyl alpha-aminoisobutyric acid (Z-Aib) containing peptides, show chemical shift nonequivalence. The magnitude of the geminal nonequivalence is correlated with the involvement of the urethane carbonyl group, in an intramolecular hydrogen bond. Studies of the model compounds Z-Aib-Aib-Ala-NHMe, and Z-Aib-Aib-Aib-Pro-OMe clearly establish the presence of intramolecular hydrogen bonds, involving the urethane CO group. In both compounds marked anisochrony of the benzylic methylene protons is demonstrated. In Z-Aib-Aib-Pro-OMe, where a 4 leads to 1 hydrogen bonded beta-turn is not possible, the benzylic-CH2-protons appear as a singlet in CDCl3 and have a very small chemical shift difference in (CD3)2SO. The observation of such nonequivalence is of value in establishing whether the amino terminal Aib-Pro beta-turn is retained in large peptide-fragments of alamethicin.
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371
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Iqbal M, Shivaji S, Vijayasarathy S, Balaram P. Synthetic peptides as chemoattractants for bull spermatozoa structure activity correlations. Biochem Biophys Res Commun 1980; 96:235-42. [PMID: 7437034 DOI: 10.1016/0006-291x(80)91205-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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372
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Vijayasarathy S, Shivaji S, Iqbal M, Balaram P. Formyl-MET-Leu-Phe induces chemotaxis and acrosomal enzyme release in bull sperm. FEBS Lett 1980; 115:178-80. [PMID: 7398874 DOI: 10.1016/0014-5793(80)81162-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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373
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Iqbal J, Yaqub M, Iqbal M. L-asparaginase--antileukemia agent--A review. J PAK MED ASSOC 1980; 30:14-7. [PMID: 6767053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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374
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Yaqub M, Rasul K, Iqbal M. Spectrophotometric determination of iodide in blood and urine. JPMA. THE JOURNAL OF THE PAKISTAN MEDICAL ASSOCIATION 1979; 29:249-50. [PMID: 118273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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375
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Pittman CUJ, Iqbal M, Chen CY, Helbert JN. Radiation degradation of poly(α-hydroxyisobutyric acid) and poly(glycollic ester). ACTA ACUST UNITED AC 1978. [DOI: 10.1002/pol.1978.170161032] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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376
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Iqbal M, Ejaz M. Selective solvent extraction of chromium(VI) using 2-hexylpyridine. J Radioanal Nucl Chem 1978. [DOI: 10.1007/bf02519407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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377
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Scott R, Patterson PJ, Burns R, Ottoway JM, Hussain FE, Fell GS, Dumbuya S, Iqbal M. Hypercalciuria related to cadmium exposure. Urology 1978; 11:462-5. [PMID: 209595 DOI: 10.1016/0090-4295(78)90157-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A work force has been investigated for possible cadmium intoxication. One group who are coppersmiths have an 18.5 per cent prevalence of upper urinary tract stone disease associated with a statistically highly significant hypercalciuria and reduced serum inorganic phosphate. Proof of exposure to cadmium has been confirmed in all workers. The trace element cadmium should be kept in mind when investigating stone formers who exhibit an unexplained hypercalciuria.
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378
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Mohammad M, Sheikh S, Iqbal M, Ahmed R, Razaq M, Khan A. Protonation of pyridinyl radicals: An electrochemical investigation. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/s0022-0728(78)80205-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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379
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Iqbal M, Ejaz M. Chemical separation of molybdenum from uranium and fission product nuclides. ACTA ACUST UNITED AC 1978. [DOI: 10.1007/bf02517151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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380
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Vicher EE, Iqbal M, Waterhouse JP. The effect of Procion Blue on certain metabolic activities of Streptococcus mutans. J Dent Res 1977; 56:977-82. [PMID: 336658 DOI: 10.1177/00220345770560082601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Metabolic activities of S mutans were selectively affected by Procion Blue, known to cause covalent bonds and stable cross links in relation to carbohydrate and protein. In this study, despite the reduction in extra polysaccharide, the level of activity of glucosyltransferase was not significantly changed from the control level and colonial morphology was not transformed from smooth to rough. The results of the investigation imply at least interference with formation of extra cellular polysaccharide, possibly in the bacterial cell wall.
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381
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382
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383
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Iqbal M. The use of 5-(4-pyridyl)nonane for the separation of chromium(vi) from fission products in hydrochloric acid media. Talanta 1975; 22:143-9. [DOI: 10.1016/0039-9140(75)80160-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/1974] [Revised: 07/18/1974] [Accepted: 08/23/1974] [Indexed: 10/18/2022]
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384
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Iqbal M, Ejaz M. The extraction of chromium(VI) from sulphuric acid solutions by 4-(5-nonyl)pyridine and its separation from fission products. Anal Chim Acta 1975. [DOI: 10.1016/s0003-2670(01)82786-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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385
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386
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Abstract
Aldolase was purified from human skeletal muscle and human liver by techniques capable of processing large quantities (10-20kg) of tissue. The methods used also proved convenient for isolating aldolase on a large scale from other mammalian and avian sources. Aldolase from both human liver and muscle was crystallized; each gave two crystalline forms, depending on the conditions of crystallization. X-ray studies on the muscle aldolase crystals suggest a close structural similarity between human and rabbit muscle aldolase. Aldolases from human muscle and liver have similar pH optima and pH stability but their stability to heat treatment differs. The effect of heat on the enzymes may therefore provide an easy means of distinguishing them. The kinetic constants K(m) and k(cat.) for these aldolases are similar to other mammalian aldolases. Amino acid analyses and tryptic peptide ;mapping' show that the primary structures of the two aldolases differ greatly.
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387
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Iqbal M, Grand NG. Biochemical events in murine cytomegalovirus-infected mouse liver. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 1973; 142:567-71. [PMID: 4347611 DOI: 10.3181/00379727-142-37068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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388
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Iqbal M, Khatry AK, Aggarwala BD. On the second fundamental problem of combined free and forced convection through vertical noncircular ducts. ACTA ACUST UNITED AC 1972. [DOI: 10.1007/bf01897849] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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389
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390
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Iqbal M. Activity of alkaline phosphatase and carbonic anhydrase in male and female zinc-deficient rats. ENZYME 1971; 12:33-40. [PMID: 4997849 DOI: 10.1159/000459512] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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391
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Busby RE, Iqbal M, Langston RJ, Parrick J, Shaw CJG. Vapour phase generation of dichlorocarbene; ring expansion of cyclic compounds accompanied by formation of fulvene derivatives. ACTA ACUST UNITED AC 1971. [DOI: 10.1039/c29710001293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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392
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Iqbal M, Wynn CH. A comparative study of rat liver, spleen and skin lysosomes. ENZYMOLOGIA BIOLOGICA ET CLINICA 1970; 11:360-8. [PMID: 4315063 DOI: 10.1159/000458372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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393
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Iqbal M. Effect of in vitro addition of zinc on alkaline phosphatase activity in the zinc-deficient rat. ENZYMOLOGIA BIOLOGICA ET CLINICA 1970; 11:412-22. [PMID: 5313498 DOI: 10.1159/000458380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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394
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Iqbal M, Dingle JT, Moore T, Sharman IM. Nutrition and lysosomal activity. The effect of dietary cod-liver oil on the distribution of polyunsaturated fatty acids in the kidney lysosomes of rats receiving deficient or adequate intakes of vitamin E. Br J Nutr 1969; 23:31-9. [PMID: 5766790 DOI: 10.1079/bjn19690006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
1. In an attempt to explain the antagonism between polyunsaturated fatty acids (PUFA) and vitamin E in the promotion of post-mortem autolysis and increased lysosomal fragility in the kidney of rats, studies were made by gas chromatography of the incorporation of PUFA into the lysosomes.2. Kidneys were taken from rats that had received various diets, which differed in their fat components and which were with or without vitamin E. Since the inclusion of cod-liver oil in the diet reduces the period of dietary preparation necessary for rapid kidney autolysis, the effect of this oil on the PUFA distribution in the lysosomes was specially studied.3. In purified preparations of kidney lysosomes from rats that had received substantial amounts of cod-liver oil for several weeks, C 20:5 acid was incorporated mainly at the expense of C 18:2 (linoleic) and C 20:4 (arachidonic) acids. In less purified lysosomal fractions the incorporation of C 20:5 and C 22:6 acids and the corresponding reductions in linoleic and arachidonic were well advanced after 10 days, but were not maximal until about 30 days. The same changes took place in the reverse direction, with about the same rapidity, when rats that had previously been given cod-liver oil were changed to a diet containing lard.4. The percentage of PUFA in the kidney lysosomes of rats not dosed with vitamin E was not significantly different from that of rats given adequate doses.5. Thus the increased tendency to kidney autolysis, and the reduced stability of the lysosomes, caused by the feeding of cod-liver oil were associated with the partial replacement of linoleic acid and of the endogenous arachidonic acid by an acid, usually foreign to the rat, which is even more unsaturated. Since vitamin E did not prevent the entry of this acid into the lysosomes its potency in retarding autolysis and stabilizing the lysosomes must be exerted at some point subsequent to the incorporation of PUFA.6. Since change in the percentage of lysosomal PUFA in response to dietary changes is slow, this suggests that the lysosornal lipidsescape usage in general metabolism as an immediate source of calories and that they have a half-life of at least 15 days. Individual fatty acids, however, may differ in their half-lives.
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395
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Busby RE, Iqbal M, Parrick J, Shaw CJG. The reaction of imidazole with dichlorocarbene in the vapour phase: a new route to the pyrimidine ring system. ACTA ACUST UNITED AC 1969. [DOI: 10.1039/c2969001344a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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396
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Iqbal M. Combined free and forced convection in a horizontal tube with uniform internal heat generation. NUCLEAR ENGINEERING AND DESIGN 1968. [DOI: 10.1016/0029-5493(68)90126-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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397
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Ahmad Y, Habib MS, Iqbal M, Qureshi MI. QUINOXALINE DERIVATIVES: VIII. THE EFFECT OF ELECTRON-DONATING GROUPS ON THE FORMATION OF CERTAIN QUINOXALINECARBOXYANILIDE N-OXIDES AND THEIR REARRANGEMENT. CAN J CHEM 1965. [DOI: 10.1139/v65-475] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Introduction of methyl or methoxy groups into the benzene ring of quinoxalinecarboxyanilide (Id), makes the resulting anilides less prone to "abnormal" oxidation (1). Normal N-oxides (IIf and IIj) were obtained from the anilides If and Ij in which the cyclic [Formula: see text] was unprotected. The methyl-substituted anilides Ig and Ih, however, on oxidation with peracetic acid gave the hydroxy derivatives (Vg and Vh) instead of the N-oxides (IIg and IIh). The methoxy-substituted anilides Ik and Il did not give the hydroxy derivatives Vk and Vl nor the expected N-oxides IIk and IIl. All the N-oxides (IIe, IIf, IIi, and IIj) on rearrangement with sulfuric acid yielded the corresponding amines IVe, IVf, IVi, and IVj. In spite of the slow rate of rearrangement of these N-oxides, attempts to isolate the intermediate hydroxyaminospirolactams (III) were unsuccessful.
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398
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Ahmad Y, Habib MS, Iqbal M, Qureshi MI, Ziauddin. Quinoxaline Derivatives. VII. The Mechanism of the Formation of 6-Chloro-1,2,3,4,2′,3′-hexahydro-4,1′-dimethyl-3,2′-dioxoquinoxaline-2-spiro-3′-indole from a QuinoxalineN-Oxide Derivative by Nucleophilic Chlorination. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1965. [DOI: 10.1246/bcsj.38.1659] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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399
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Ahmad Y, Habib MS, Iqbal M, Ziauddin. Quinoxaline Derivatives. V. Some Reactions of 2-Cyano-3-hydroxyquinoxaline 1-Oxide. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1965. [DOI: 10.1246/bcsj.38.562] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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400
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Ahmad Y, Habib MS, Iqbal M, Qureshi MI, Craig JC, Garnett JL, Temple DM, Fischer A, Happer DAR, Vaughan J, Albert A, Willette RE, Daly JJ, Banks RE, Haszeldine RN, Sutcliffe H, Beer RJS, Slater RA, Griffith WP, Benn MH, Fields EK, Beard JH, Plesch PH, Carruthers W, Douglas AG, Battersby AR, Francis RJ, Johnson AW, Oldfield D, Rodrigo R, Shaw N, Clifford DR, Woodcock D, Edwards RL, Kale N, Birch AJ, White DA, Edwards AJ, Mouty MA, Peacock RD, Suddens AJ. Notes. ACTA ACUST UNITED AC 1964. [DOI: 10.1039/jr9640004053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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