scholarly journals 67 kDa calcimedin, a new Ca2+-binding protein

1986 ◽  
Vol 238 (1) ◽  
pp. 49-54 ◽  
Author(s):  
P B Moore

A set of four proteins, termed calcimedins, are isolatable from smooth, cardiac and skeletal muscle by using a fluphenazine-Sepharose affinity column. The calcimedins show apparent Mr values of 67,000, 35,000, 33,000 and 30,000 by SDS/polyacrylamide-gel electrophoresis. The 67,000-Mr calcimedin (67 kDa calcimedin) has now been purified to homogeneity by using DEAE-cellulose chromatography followed by Ca2+-dependent binding to phenyl-Sepharose. The amino acid analysis of the 67 kDa calcimedin shows this protein does not contain trimethyl-lysine but does contain 2 mol of tryptophan/mol of protein. The 67 kDa calcimedin shows positive ellipticity in the near-u.v. range with c.d. Ca2+-binding studies indicate one high-affinity Ca2+-binding site with Kd 0.4 microM. The data show that the 67 kDa calcimedin is distinct from other Ca2+-binding proteins described to date.

1969 ◽  
Vol 113 (3) ◽  
pp. 489-499 ◽  
Author(s):  
C. R. Parish ◽  
G. L. Ada

1. Flagellin, isolated from the flagella of Salmonella adelaide, was shown by various criteria to be a pure protein. It had a molecular weight of about 40000 and contained three methionine, six tyrosine, 11 arginine and 25 lysine residues/mol., of which 11 of the lysine residues were present as ∈-N-methyl-lysine. 2. After treatment of flagellin with cyanogen bromide in formic acid, four main fragments (A, B, C and D) were obtained, with as many as six minor components that represented partial degradation products. The major fragments were estimated by amino acid analysis to have molecular weights of about 18000 for fragment A, 12000 for fragment B, 5500 for fragment C and 4500 for fragment D. Fragments A, B and D, but not fragment C, were recovered pure by gel chromatography as monitored by polyacrylamide-gel electrophoresis. 3. A complex between fragments C and D was also isolated (mol.wt. 10000) after limited oxidation of flagellin by chloramine-t before digestion by cyanogen bromide. After oxidation essentially only two fragments were released from flagellin by cyanogen bromide: the ‘C,D’ complex and a presumed ‘AB’ fragment. 4. The sum of the amino acid analyses of fragments A and B and the ‘C,D’ complex gave residue values that agreed well with the amino acid composition of native flagellin. 5. Fragments A and D contained tyrosine, and ten of the 11 ∈-N-methyl-lysine residues of the molecule were in fragment A. Reaction with [125I]iodide at small extents of substitution showed that, in flagellin, the tyrosine residue of fragment D was more readily substituted than those of fragment A. By contrast, in polymerized flagellin, the tyrosine residues of fragment A were more readily substituted. 6. Treatment of flagellin with carboxypeptidases A and B revealed the C-terminal sequence -Leu-Leu-Leu-Arg. Arginine and leucine were released by carboxypeptidase from the ‘C,D’ complex but not from fragment D, indicating that fragment C was C-terminal. 7. On the basis of the results from amino acid analysis, carboxypeptidase digestion, N-terminal analysis, iodination studies and polyacrylamide-gel electrophoresis, the sequence of fragments in flagellin was considered to be B–A–D–C; in the polymer, fragment A was exposed. It is suggested that methylation of the lysine residues occurred in the organism after flagellin had polymerized.


1982 ◽  
Vol 201 (1) ◽  
pp. 71-79 ◽  
Author(s):  
R Dayal ◽  
J Hurlimann ◽  
Y M L Suard ◽  
J P Kraehenbuhl

Caseins were separated from whey proteins by acid precipitation of skimmed rabbit milk. Whole casein was resolved by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis into three major bands with apparent relative molecular masses (Mr of 31 000, 29 000 and 25 000. On agarose/urea-gel electrophoresis whole casein gave three bands with electrophoretic mobilities alpha, beta and gamma. The three components were purified by DEAE-cellulose chromatography under denaturing and reducing conditions. Each was shown to have a different amino acid, hexose and phosphorus content, as well as non-identical peptide fragments after proteinase digestion. The 31 000 Da (dalton) protein, of alpha-electrophoretic mobility, had a high phosphorus content (4.38%, w/w); the 29 000 Da peptide, of gamma-mobility, had the highest hexose content (2.2%, w/w), contained 0.8 cysteine residue per 100 amino acid residues and was susceptible to chymosin digestion corresponding thus to kappa-casein; the 25 000 Da protein migrated to the beta-position. The rabbit casein complex is composed of at least three caseins, two of which (alpha- and kappa-caseins) are analogous to the caseins from ruminants. Although caseins are poor immunogens, specific antibodies were raised against total and purified polypeptides. The antiserum directed against whole casein recognized each polypeptide, each casein corresponding to a distinct precipitation line. The antisera directed against each casein polypeptide reacted exclusively with the corresponding casein and no antiserum cross-reaction occurred between the three polypeptides. From whey, several proteins were isolated, characterized and used as antigens to raise specific antibodies. An iron-binding protein with an apparent Mr of 80 000 was shown to be immunologically and structurally identical with serum transferrin.


1988 ◽  
Vol 256 (3) ◽  
pp. 797-805 ◽  
Author(s):  
L Bush ◽  
T J McGahan ◽  
H B White

BBP-II, the major biotin-binding protein from chicken oocytes, was purified 12,000-fold with a 22% yield. The purification procedure includes butan-1-ol extraction of yolk lipids, phosphocellulose chromatography of the water-soluble proteins, DEAE-cellulose chromatography at pH 7.4 and hydroxyapatite column chromatography. Final purification was obtained by using a second DEAE-cellulose column chromatography at pH 6.0. BBP-I activity separated from BBP-II activity during elution from the first DEAE-cellulose column. Purified BBP-II was homogeneous on both polyacrylamide-gel electrophoresis and SDS/polyacrylamide-gel electrophoresis under conditions that would detect a 1% impurity. The subunit Mr determined from SDS/polyacrylamide-gel electrophoresis was 18,200 (72,600 for tetramer), which compares favourably with an Mr value of 17,300 (69,100) calculated from the amino acid analysis. A single precipitin line formed when rabbit antiserum to the protein was directed against a crude chicken egg-yolk sample. BBP-II purified by this procedure lacked carbohydrate and phosphate, was stable indefinitely when frozen, and was quite stable at room temperature. The N-terminal amino acid sequence showed polymorphism at three positions in the first 23 residues and was about 45% identical with the N-terminal 22 residues of avidin. Antiserum to BBP-II cross-reacted with BBP-I and similar proteins in the yolk of eggs from various birds and alligator as judged by immunodiffusion and enzyme-linked immunosorbent assays. No cross-reaction was observed with chicken egg-white by either of these methods.


1987 ◽  
Vol 242 (3) ◽  
pp. 895-903 ◽  
Author(s):  
J Radojković ◽  
T Ureta

The purification to homogeneity of hexokinases B and C from the cytosol of rat Novikoff hepatoma was achieved by a protocol using an initial chromatography on Blue 2-agarose to separate the isoenzymes from each other. After that step each hexokinase was subjected to chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-300, followed by re-chromatography on hydroxyapatite. The final preparations of hexokinases B and C had specific activities of 86 and 23.5 units/mg of protein respectively, and gave single bands on electrophoresis under non-denaturing conditions or in SDS/polyacrylamide gels. Mr values of about 100,000 were found for both isoenzymes either by Sephacryl S-300 chromatography or by SDS/polyacrylamide-gel electrophoresis. Values of apparent Km for glucose and ATP of pure hexokinase B were similar to those reported for the enzyme from other sources. The apparent Km value for glucose of hexokinase C was 0.025 mM. Marked inhibition of hexokinase C by glucose concentrations above 0.2 mM was found. The effect was partially relieved by ATP concentrations above 1 mM and was independent of pH. Glucose 6-phosphate was inhibitory, but the Ki value (0.18 mM) is higher than those reported for other animal hexokinases. The amino acid composition of hexokinase C was found to be similar to those reported for hexokinases B and D. Also, an immune serum directed against hexokinase A was able, at low dilutions, to bind hexokinases B and C. An immune serum directed against hexokinase C was able, at low dilutions, to bind hexokinase B and also, but weakly, hexokinase A.


1976 ◽  
Vol 159 (3) ◽  
pp. 697-705 ◽  
Author(s):  
A L Latner ◽  
A W Hodson

A method is presented for the preparation of human liver alkaline phosphatase (orthophosphoric monoester phosphohydrolase, EC 3.1.3.1). The method gives a purification factor of 12.5 × 10(3) over the initial aq. butan-1-ol extract, a recovery of 6.0% and a specific activity for the preparation of 1450-1550 units/mg of protein, 1 unit being defined as the amount of enzyme catalysing the hydrolysis of 1mumol of p-nitrophenyl phosphate/min at 35 degrees C in 0.1 M-2-amino-2-methylpropan-1-ol/HCl buffer, pH 10.5, containing 10mM-p-nitrophenyl phosphate. Homogeneity was studied by ultracentrifugation, by immunoelectrophoresis and by polyacrylamide-gel electrophoresis. A single contaminating protein was present which was less than 5% of the total. Ultracentrifugation and equilibrium-gradient-pore electrophoresis techniques indicated a mol.wt. of 156000 and 160000 respectively. Equilibrium-gradient-pore electrophoresis indicated that the alkaline phosphatase molecule is possibly a dimer, comprising two subunits of about 80000 mol.wt. Amino acid analysis proved remarkably similar to that for alkaline phosphatase from other sources, regardless of species.


1980 ◽  
Vol 191 (2) ◽  
pp. 333-339 ◽  
Author(s):  
G M Sainsbury ◽  
B Bullard

Z-discs were isolated from Lethocerus (waterbug) flight muscle by removing the contractile proteins from myofibrils with a solution of high ionic strength. Sodium dodecyl sulphate (SDS)/polyacrylamide-gel electrophoresis confirmed a previous report that major Z-disc proteins had subunit mol.wts of 200 000, 180 000, 105 000, 95 000, 42 000 and 35 000. A protein of subunit mol.wt 25 000 was found in once-washed Z-discs but was degraded or was removed by successive washes. In addition, a protein of high molecular weight (less than 300 000) was found in Z-discs. Proteins of subunit mol.wts. 42 000, 35 000 and 25 000 were individually sliced from SDS/polyacrylamide gels and eluted. Amino acid analysis showed that the 35 000-subunit-mol.wt. protein was not, as was previously suggested, tropomyosin, but was a distinct Z-disc protein rich in proline. Calculations based on the amino acid analysis showed that this protein contained substantial hydrophobic regions. Preliminary investigations into the isoelectric point and a method of isolation of the 35 000-subunit-mol.wt. Z-disc protein are described. This protein was found in slices cut from SDS/polyacrylamide-gel electrophoretograms of whole myofibrils. The protein of 42 000 subunit mol.wt. was shown by amino acid analysis to be actin and the 25 000-subunit-mol.wt. Z-disc protein was proline-rich.


1989 ◽  
Vol 264 (3) ◽  
pp. 813-822 ◽  
Author(s):  
S Grenfell ◽  
N Smithers ◽  
K Miller ◽  
R Solari

In this study we demonstrate that 125I-labelled interleukin (IL) 1 alpha binds specifically to its receptor on the surface of EL4 6.1 cells and is subsequently endocytosed and translocated from the cell membrane to the nucleus, where it progressively accumulates. Two-dimensional polyacrylamide-gel electrophoresis revealed that the internalized 125I-IL1 alpha associated with the nucleus was intact, with negligible breakdown products present. Specific and saturable binding of 125I-IL1 alpha was demonstrated on purified nuclei isolated from these cells. Binding of the radiolabelled ligand showed similar kinetics to that of the plasma-membrane receptor, and was inhibited by both unlabelled IL1 alpha and IL1 beta. Equilibrium binding studies on isolated nuclei revealed a single high-affinity binding site, with a Kd of 17 +/- 2 pM, and 79 +/- 12 binding sites per nucleus. These studies demonstrate that receptor-mediated endocytosis of IL1 results in its accumulation in the nucleus, and this mechanism may play an important role in mediating some of the actions of IL1.


1978 ◽  
Vol 169 (3) ◽  
pp. 589-596 ◽  
Author(s):  
A Koj ◽  
M W C Hatton ◽  
K L Wong ◽  
E Regoeczi

Alpha1-Antitrypsin was isolated from rabbit plasma by salting out with (NH4)2SO4 followed by ion-exchange chromatography either on DEAE-Sephadex or DEAE-cellulose (each at pH8.8 and 6.5), and affinity chromatography on Sepharose-Cibacron Blue and Sepharose-concanavalin A. The protein thus obtained was homogeneous during crossed immunoelectrophoresis by using an antiserum to whole rabbit plasma, but it migrated as two broad bands when electrophoresed in alkaline polyacrylamide gels. Under optimal loading conditions, two or three subcomponents could be distinguished in each band. The two major forms of rabbit alpha1-antitrypsin, designated components F and S, were separated by preparative polyacrylamide-gel electrophoresis, and some of their physico-chemical properties were established. Both forms reacted with trypsin at a molar ratio of 1:1. Their elution volumes from a Sephadex G-200 column were identical, corresponding to a mol.wt. of 58000; however, some heterogeneity was observed after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Isoelectric focusing in polyacrylamide gel in a pH 4-6 gradient revealed a multiple-band pattern for each form in the range of pH4.4-4.9. The two forms of rabbit alpha1-antitrypsin possessed the same N-terminal amino acid (glutamic acid) and had very similar amino acid and carbohydrate compositions.


1976 ◽  
Vol 29 (2) ◽  
pp. 1 ◽  
Author(s):  
Robert C Marshall ◽  
JM Gillespie

The heterogeneity of the reduced and S-carboxymethylated high-sulphur protein fraction from mouse hair has been examined by chromatography and polyacrylamide gel electrophoresis at pH values above and below the isoelectric region. Considerable heterogeneity is observed both in size (molecular weight range 12000-45000) and in charge. Amino acid analysis of a number of column chromatographic fractions shows the high-sulphur proteins to be largely composed of proteins with a carboxymethy1cysteine content above 25 residues per 100 residues and a pronounced heterogeneity in arginine content. Their chromatographic behaviour is similar to that observed for the ultra-high-sulphur proteins from wool.


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