Document Detail


Protein characteristics of thrombopoietin.
MedLine Citation:
PMID:  11012214     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Thrombopoietin (TPO) was purified from irradiated thrombocytopenic rat plasma. In the process of purification, some biochemical and biological characteristics were investigated. Rat plasma TPO was extremely hydrophobic and exhibited multiple peaks of activity on gel filtration. Both the low and high molecular weight fractions were separately subjected to further purification. Consequently, a rat TPO cDNA was cloned based on the amino acid sequences of purified rat plasma TPO. It revealed that each final purified rat plasma TPO was not a full-length form. In addition, rat hepatocytes and three rat hepatoma cell lines were found to produce rat TPO. Each native TPO derived from cultured cells was also partially purified, and hepatocyte-derived TPOs were shown to be heterogeneous in molecular weight. To study the structure of TPO, various recombinant TPO molecules were generated. Two disulfide bonds (Cys7-Cys151 and Cys29-Cys85) located in the N-terminal domain of TPO have an important effect on its biological activity. The human TPO muteins, sequentially deleted from the C-terminal, were expressed in COS-1 cells. TPO (1-151) was active, but TPO (1-150), which lacks Cys151, did not exhibit TPO activity. These findings indicate that the region essential for TPO activity is the N-terminal domain, which contains two disulfide bonds. Although the role(s) of the C-terminal domain is not clear at present, the potential N-glycosylation in the C-terminal domain is not directly required for exhibiting TPO activity.
Authors:
T Kato
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Stem cells (Dayton, Ohio)     Volume:  14 Suppl 1     ISSN:  1066-5099     ISO Abbreviation:  Stem Cells     Publication Date:  1996  
Date Detail:
Created Date:  2000-10-02     Completed Date:  2000-11-02     Revised Date:  2005-11-16    
Medline Journal Info:
Nlm Unique ID:  9304532     Medline TA:  Stem Cells     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  139-47     Citation Subset:  IM    
Affiliation:
Pharmaceutical Research Laboratory, Kirin Brewery Co., Ltd., Maebashi, Gunma, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
COS Cells
Carcinoma, Hepatocellular / metabolism
Chromatography, Gel
DNA, Complementary / metabolism
Disulfides
Dogs
Electrophoresis, Polyacrylamide Gel
Humans
Liver / metabolism
Liver Neoplasms / metabolism
Mice
Mutation
Protein Structure, Tertiary
Rats
Recombinant Proteins / chemistry
Thrombopoietin / blood,  chemistry*,  genetics,  isolation & purification
Tumor Cells, Cultured
Chemical
Reg. No./Substance:
0/DNA, Complementary; 0/Disulfides; 0/Recombinant Proteins; 9014-42-0/Thrombopoietin

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