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Biomedical subjects

M Jahan

Publications and source records attributed to M Jahan.

14 recordsLinked to original sources
PubMed1992

Carnivora: the primary structure of the major hemoglobin component from adult European lynx (Lynx lynx, Felidae).

The complete primary structure of the major hemoglobin component from the adult European lynx (Lynx lynx) is presented. Presence of two hemoglobin components and three chains, beta A, beta B, and alpha, identified by gel electrophoresis. The purification of the globin chains achieved by ion-exchange chromatography. The globin chains were digested with trypsin. The peptide generated were purified by reversed-phase HPLC. Sequencing of the native chains up to 42 cycles and of the tryptic peptides were deduced by Edman degradation in liquid- and gas-phase sequencer. The primary structure established aligned with those of human Hb-A. The comparison of lynx globin chains with other representatives of the Felidae, lion, tiger, jaguar, leopard, and cat revealed high homology.

Amino Acid Sequence↗
PubMed1991

The complete primary structure of the marine Carnivora, galapagoes fur seal (Arctocephalus galapagoensis, Otariidae) hemoglobins.

The complete primary structure of the two hemoglobin components of the fur seal (Arctocephalus galapagoensis) is presented. The two components (HbI and HbII) occur in nearly equal amounts and have identical beta-chains; whereas the two alpha-chains (alpha I/alpha II) differ by six exchanges Ile/Val, Met/Thr, Ser/Ala, Pro/His, Lys/Gly, and Thr/Ala at positions 10, 34, 35, 50, 78, and 131, respectively. The components were isolated by DEAE-Sephacel chromatography and were separated into the globin chains by RP-HPLC on a column of Nucleocil-C4. The sequences have been determined by Edman degradation in liquid- and gas-phase sequencer, using the native chains and tryptic peptides. The sequences compared with those of other Carnivora species and an adult human globin chains. An identical beta-chain is found in fur seal and walrus, whereas larger differences were found between alpha I and alpha II compared to beta-chains.

Amino Acid Sequence↗
PubMed1990

Carnivora: the primary structure of hemoglobin from adult coati (Nasua nasua rufa, Procyonidae).

The complete primary structure of the hemoglobin from the adult coati (Nasua nasua rufa) is presented. The erythrocytes contain one hemoglobin component and two globin chains. The isolation of globin chains was achieved by reversed-phase HPLC on a column of Nucleosil-C4. The primary structures of globin chains and tryptic peptides was determined in liquid- and gas-phase sequenators. The sequence of the alpha and beta-chains of coati compared with those of other Carnivora species. Results are discussed with respect to structural variations and the phylogenetic relationship.

Amino Acid Sequence↗
PubMed1990

Characterization and expression of uterine and placental alkaline phosphatases in the mouse.

Alkaline phosphatase (ALP) is rapidly induced in the uterine subepithelial stroma after a natural or artificial decidual stimulus. During gestation ALP-specific activity peaked at Day 7 to 8 (Day 1 is day of detection of the copulation plug) followed by a rapid decline to control levels by Day 9. This elevation in enzyme activity was preceded by an 8-fold induction of a 2.6 kilobase (kb) mRNA. This mRNA was not preferentially localized to implantation sites. ALP activity was detected in the placenta at Day 9 and reached maximum specific activity at Day 19. The placental ALP was also encoded by a 2.6 kb mRNA. Uterine and placental ALPs were inhibited to the same extent by levamisole, L-tryptophan and homoarginine. The calculated Ki values for these inhibitors were not statistically different between the uterine and placental forms. Km values towards the substrate p-nitrophenylphosphate, however, were statistically different between the uterine and placental forms. Both uterine and placental ALPs were stimulated 3-4-fold by addition of 2 mM-Mg2+. Electrophoretic mobilities on SDS polyacrylamide gel, where the enzyme migrated as a single band, were the same. The uterine form, however, could be distinguished from the placental isoenzyme by separation on non-denaturing polyacrylamide gels; the uterine form had a single zone of activity which migrated with an intermediate mobility between the two zones of activity detected for the placental enzyme. These differences in mobility could be ascribed to the sialic acid content of the enzyme because treatment with neuraminidase resulted in the uterine and placental forms migrating with comparable but slower mobilities in non-denaturing gels.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1989

Carnivora: the amino-acid sequence of the adult Sumatran tiger (Panthera tigris sumatrae) hemoglobins.

The complete amino-acid sequences of the hemoglobins from the adult Sumatran tiger (Panthera tigris sumatrae) have been determined on automatic liquid- and gas-phase sequenators. The globin chains were isolated by reverse phase HPLC on a column of Nucleosil-C4. N-Acetylserine was detected by FAB-mass spectroscopy as N-terminal aminoacid residue of the beta I chain. Comparing the sequences of the globin chains of the tiger with that of human Hb-A, 23 substitutions were recognized in the alpha, 29 in beta I and 28 in the beta II chain.

Amino Acid Sequence↗
PubMed1988

Study of the mechanism by which the Na+-Pi co-transporter of mouse kidney proximal-tubule cells adjusts to phosphate depletion.

1. Proximal-tubule cells isolated from mouse kidney after digestion with collagenase take up Pi by an Na+-dependent and saturable process mediated by the Na+-Pi co-transporter of the brush-border membrane. 2. Pi depletion of the cells is accompanied by a stimulation of Pi-transport activity. Kinetic investigations reveal that Vmax. is increased by 90% and Km decreased by 50% after Pi depletion. Transport activity returns to normal values after incubation for 30 min at 37 degrees C of Pi-depleted cells in normal medium containing 1 mM-Pi, but the fall in transport activity under these conditions is inhibited by colchicine. 3. The energy of activation of Na+-Pi co-transport activity of depleted cells differs greatly from that found for normal replete cells. 4. The results provide evidence that stimulation of transport by Pi depletion arises from an increase in the number of carrier sites in the brush-border membrane. Additionally, changes in the properties of the transporter occur which may reflect altered phospholipid-carrier-protein interaction in the Pi-depleted condition.

Animals↗
PubMed1987

The primary structure of the hemoglobins of the adult jaguar (Panthera onco, Carnivora).

The primary structure of the hemoglobins from Jaguar (Panthera onco) are presented. Electrophoretic separations without and with a dissociating agent revealed the presence of two hemoglobin components, alpha 2 beta I2 and alpha 2 beta II2. The separation of the hemoglobin components was achieved by ion-exchange chromatography. The globin chains were separated by ion-exchange chromatography and also by reversed phase HPLC. The amino-acid sequences of the native chains and peptides were determined by liquid-phase and gas-phase sequencing. N-Acetylserine was detected by FAB-mass spectroscopy as N-terminal group of the beta I chain. The sequences are compared with that of human hemoglobin (Hb A).

Amino Acid Sequence↗
PubMed1986

Alkaline phosphatase of chick kidney.

The alkaline phosphatase prepared from kidneys of domestic chicks is a tetramer (Mr 270,000) consisting of identical subunits (Mr 68,000). The tetramer may be dissociated by detergent treatment to a dimer (Mr 150,000) with no loss of catalytic activity. The tetramer probably represents the in vivo state. The enzyme is stimulated by Mg2+ and inhibited noncompetitively by Zn2+ and levamisole. The stimulation and inhibition show similar pH dependencies. Evidence for an essential histidine is provided by sensitivity of the enzyme to diethyl pyrocarbonate. It is suggested that chick kidney and bone phosphatases could be expressed by different genes.

Alkaline Phosphatase↗
PubMedDate not supplied

Carnivora: the amino acid sequence of the adult European mink (Mustela lutreola, Mustelidae) hemoglobins.

The complete amino acid sequences of the hemoglobins from the adult European mink (Mustela lutreola) are presented. The erythrocytes contain two hemoglobin components and three globin chains. The isolation of globin chains achieved by ion-exchange chromatography on a column of CM-cellulose in 8 M urea buffer. The primary structure of globin chains and of the tryptic peptides determined in liquid- and gas-phase sequenators. The alignment of the alpha- and beta-chains with those of reported sequences from other carnivora species belonging to the family Mustelidae may give an insight into the evolution of this molecule.

Amino Acid Sequence↗