scholarly journals Synthetic, structural and biological studies of the ubiquitin system: the total chemical synthesis of ubiquitin

1994 ◽  
Vol 299 (1) ◽  
pp. 151-158 ◽  
Author(s):  
R Ramage ◽  
J Green ◽  
T W Muir ◽  
O M Ogunjobi ◽  
S Love ◽  
...  

The small protein ubiquitin (76 amino acids) has been synthesized under optimized conditions by Merrifield solid-phase methodology using the N alpha-Fmoc protecting group. The crude polypeptide mixture was purified to homogeneity by gel filtration, dialysis and a combination of cation- and anion-exchange chromatography to yield ubiquitin. Amino acid analysis, enzymic digestion and sequencing by automated Edman degradation were used to authenticate the primary structure. Isoelectric focusing and m.s. were used to demonstrate that the final product was greater than 98% pure with a final yield of 93 mg (4.3%) from a single synthesis on a 0.25 nmol scale.

1988 ◽  
Vol 53 (11) ◽  
pp. 2952-2956 ◽  
Author(s):  
Bernard Lammek ◽  
Zbigniew Maćkiewicz ◽  
Izabela Derdowska ◽  
Hanna Świderska ◽  
Adam Nowosławski ◽  
...  

Two peptide fragments of hepatitis B surface antigen pre-S2 region were synthesized by the solid phase method. The peptides were purified by gel filtration or ion-exchange chromatography on Sephadex SP-C-25. Both peptides induced a cellular and humoral immune response in rabbits. The results showed that fragment 14-22 of pre-S2 region contains one of the antigenic determinants.


1980 ◽  
Vol 187 (3) ◽  
pp. 647-653 ◽  
Author(s):  
K Arakawa ◽  
M Yuki ◽  
M Ikeda

Tryptensin, a vasopressor substance generated from human plasma protein fraction IV-4 by trypsin, has been isolated and the amino acid composition analysed. The procedures used for the isolation were: (a) adsorption of the formed tryptensin on Dowex 50W (X2; NH4+ form); (b) gel filtration through Sephadex G-25; (c) cation-exchange chromatography on CM-cellulose; (d) anion-exchange chromatography on DEAE-cellulose; (e) re-chromatography on CM-cellulose; (f) gel filtration on Bio-Gel P-2; (g) partition chromatography on high-pressure liquid chromatography. The homogeneity of the isolated tryptensin was confirmed by thin-layer chromatography and thin-layer electrophoresis. The amino acid analysis of the hydrolysate suggested the following proportional composition: Asp, 1; Val, 1; Ile, 1; Tyr, 1; Phe, 1; His, 1; Arg, 1; Pro, 1. This composition is identical with that of human angiotensin.


Author(s):  
Nguyen Thi My Trinh ◽  
Tran Linh Thuoc ◽  
Dang Thi Phuong Thao

Background: The recombinant human granulocyte colony stimulating factor con-jugated with polyethylene glycol (PEGylated GCSF) has currently been used as an efficient drug for the treatment of neutropenia caused by chemotherapy due to its long circulating half-life. Previous studies showed that Granulocyte Colony Stimula-ting Factor (GCSF) could be expressed as non-classical Inclusion Bodies (ncIBs), which contained likely correctly folded GCSF inside at low temperature. Therefore, in this study, a simple process was developed to produce PEGylated GCSF from ncIBs. Methods: BL21 (DE3)/pET-GCSF cells were cultured in the LiFlus GX 1.5 L bioreactor and the expression of GCSF was induced by adding 0.5 mM IPTG. After 24 hr of fermentation, cells were collected, resuspended, and disrupted. The insoluble fraction was obtained from cell lysates and dissolved in 0.1% N-lauroylsarcosine solution. The presence and structure of dissolved GCSF were verified using SDS-PAGE, Native-PAGE, and RP-HPLC analyses. The dissolved GCSF was directly used for the con-jugation with 5 kDa PEG. The PEGylated GCSF was purified using two purification steps, including anion exchange chromatography and gel filtration chromatography. Results: PEGylated GCSF was obtained with high purity (~97%) and was finally demonstrated as a form containing one GCSF molecule and one 5 kDa PEG molecule (monoPEG-GCSF). Conclusion: These results clearly indicate that the process developed in this study might be a potential and practical approach to produce PEGylated GCSF from ncIBs expressed in Escherichia coli (E. coli).


1977 ◽  
Author(s):  
T. Exner ◽  
K.A. Rickard ◽  
H. Kronenberg

Factor VTII tends to become less stable the greater its degree of purification. The loss of factor VIII during preparation of high activity concentrates makes such processes uneconomical. Conditions contributing to the stability of factor VIII were investigated.High purity factor VIII was incubated with plasma components fractionated by gel filtration and by anion exchange chromatography. Factor VIII activity was assessed initially and after several hours incubation. Several fractions destroying factor VIII activity were clearly resolved. Fractions stabilizing factor VIII were associated only with albumin.Various buffer systems were investigated similarly. A non-chelating buffer system containing albumin was found to give optimal factor VIII stability.


Author(s):  
S Yoshimoto ◽  
M Hirota ◽  
C Ohboshi ◽  
K Shima

Acid-urea extract of rat brain was examined by glucagon-like peptide-1 (GLP-1) specific radioimmunoassay. A single peak was observed which co-eluted with GLP-1(7–36)amide on gel filtration and anion exchange chromatography. In contrast, GLP-1(1–37) was not detected under our experimental conditions. The fact that GLP-1 (7–36)amide, but not GLP-1(1–37), was present in rat brain suggests that preproglucagon was processed in the brain in the same manner as in the intestine and not as in the pancreas.


1980 ◽  
Vol 33 (3) ◽  
pp. 279 ◽  
Author(s):  
RN Murdoch ◽  
Louise E Buxton ◽  
DJ Kay

An improved procedure for the purification of alkaline phosphatase from about 10 g of day 7 pregnant mouse uterine tissue is described. Following homogenization, the procedure involved solubilization and extraction with 0�8% (v/v) Triton X-lOO and 20% (v/v) n-butanol, ammonium sulfate precipitation, concanavalin A-Sepharose 4B affinity chromatography, DEAE-cellulose anion-exchange chromatography and Sephacryl S200 gel filtration. On subjecting 2162-fold purified enzyme preparations to polyacrylamide-gel electrophoresis, a single band of protein coincident with the zone of enzyme activity and having an apparent molecular weight of 205 OOO� lOOOO was identified. Affinity chromatography yielded the largest increase in purity of any step in the procedure and established the glycoprotein nature of the uterine enzyme.


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