Production of antibody to phosphoprotein associated with nucleosome structure

1982 ◽  
Vol 60 (3) ◽  
pp. 356-363 ◽  
Author(s):  
M. S. Zhao ◽  
C. C. Liew

Antibodies were produced to phosphoprotein fraction, and a phosphoprotein B2 obtained by carboxyl methyl cellulose column chromatography and sodium dodecyl sulfate (SDS) – polyacrylamide gel electrophoresis as described previously (Biochem. J. 183, 147 (1979)). Production of the specific antibody was confirmed by double immunodiffusion. The phosphoprotein B2 (relative mass 68 000), which was isolated from the phosphoprotein fraction by SDS–polyacrylamide gel electrophoresis, specifically reacted with the antisera, as identified by "rocket" immunoelectrophoresis. Further characterization of the antibody to the phosphoprotein was carried out by isoelectrofocusing gel electrophoresis. The phosphoprotein, previously identified in the isoelectric point (pI) region 6.2–8.5, was subsequently reacted with antisera and 125I-labelled protein A. A prominent radioactive peak was identified in the region in which the phosphoprotein was focused. The radioimmunoactivity was proportional to the amount of phosphoproteins present in the isoelectric focusing gel. The presence of phosphoprotein in two types of mononucleosomes (MN1 and MN2) was demonstrated immunologically by use of the phosphoprotein antibody. The relationship between the phosphoprotein and chromatin structure, and possible role in gene regulation is discussed.

1982 ◽  
Vol 60 (4) ◽  
pp. 463-470 ◽  
Author(s):  
T. Youdale ◽  
J. P. MacManus ◽  
J. F. Whitfield

Two nonidentical subunits of mammalian ribonucleotide reductase, L1 and L2, from regenerating rat liver have been extensively purified for the first time. They were separated by dATP-Sepharose affinity chromatography. Subunit L1, which bound to dATP-Sepharose, was eluted with 50 mM ATP and purified to homogeneity (as demonstrated by sodium dodecyl sulfate (SDS) – polyacrylamide gel electrophoresis) by molecular exclusion high-pressure liquid chromatography (HPLC). This subunit had an apparent relative mass (Mr) of 45 000 and a Km of 0.9 × 10−4 for CDP. Subunit L2, which did not bind to dATP-Sepharose, was purified by pH 5.2 precipitation followed by chromatography on CM-Sephadex, molecular exclusion HPLC, and DEAE-cellulose. This subunit contained iron and had an apparent Mr of 120 000 by HPLC molecular exclusion chromatography, but showed two bands (Mr 75 000 and Mr 47 000) on SDS–polyacrylamide gel electrophoresis. Neither L1 nor L2 separately had any enzyme activity but when combined they reduced CDP to dCDP.


1983 ◽  
Vol 61 (2-3) ◽  
pp. 130-136 ◽  
Author(s):  
Bertram W. Griffiths ◽  
André Godard

A three-step procedure for the purification of pregnancy-specific β1-glycoprotein (PSβ1G) on a milligram scale from maternal serum has been developed. The principal purification was achieved by the use of an immunoadsorbent and the remaining impurities were removed by hydroxylapatite chromatography and negative affinity chromatography. The overall procedure resulted in the purification of approximately 10 mg of PSβ1G which represented about 21% of PSβ1G in 300 mL of serum. The PSβ1G was of high purity as shown by analytical polyacrylamide gel electrophoresis, sodium dodecyl sulfate – polyacrylamide gel electrophoresis, and immunochemical tests. Experiments by immunoelectrophoresis and gel chromatography indicate that the electrophoretic mobility and relative mass of the purified PSβ1G are very similar to those of the native serum protein. Structural analysis of PSβ1G suggests that it is composed of two identical subunit chains bonded noncovalently. However, a trimeric structure for PSβ1G cannot be ruled out based on the uncertainty of relative mass estimates by gel chromatography in nondenaturing solvent. The anomalous characteristics of a previous purified polymeric form of PSβ1G (PSβ1G-I) are discussed in relation to the new findings presented here.


1984 ◽  
Vol 219 (3) ◽  
pp. 971-978 ◽  
Author(s):  
M Sudol ◽  
E Reich

The plasminogen activator secreted by calcitonin-treated pig kidney cells was purified, characterized and compared with human urinary urokinase. The purification procedure was based on the following steps: sulphopropyl-Sephadex chromatography, p-aminobenzamidine-Sepharose chromatography, preparative sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and isoelectrofocusing. The purified enzyme was obtained from the conditioned medium with a yield of 13% and a purification factor of 390-fold. Analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis under non-reducing conditions showed one closely spaced doublet with an Mr of 50 000; in the presence of reducing agents, two additional bands of Mr 30 000 and 20 000 appeared. The purified enzyme resembles the 53 000-Mr components of human urinary urokinase in amino acid composition and two-dimensional tryptic peptide maps and in its catalytic properties, and the two enzymes cross-react immunologically with rabbit antibodies raised against either. The enzyme appears to be different from tissue plasminogen activator secreted by HeLa cells.


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