The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.
wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Expression of rat phosphoribosylpyrophosphate synthetase subunits I and II in Escherichia coli. Isolation and characterization of the recombinant isoforms.

The 34-kDa subunit of rat liver phosphoribosylpyrophosphate synthetase is a mixture of the two highly homologous isoforms, PRS I and PRS II. Heretofore, it was not possible to separate the two. We now describe isolation and characterization of the recombinant isoforms, named rPRS I and rPRS II. The respective rat cDNAs were inserted into vectors constructed from pKK233-2 by replacing its replication origin with that of pGEM-1 and expressed in Escherichia coli. The rPRS I and rPRS II were purified to apparent homogeneity with specific activities of 33,400 and 46,200 milliunits/mg, respectively; these values were at least 2.5-fold higher than the highest value for the mammalian enzyme so far reported. Both isoforms showed a similar dependency on Pi as an absolute activator. Sulfate partially substituted for Pi. The maximal activities of rPRS I and rPRS II with sulfate were 43 and 7%, respectively, of those seen with Pi. The two isoforms differed in sensitivity to inhibition by ADP and GDP. Inhibition of rPRS I and rPRS II by 0.3 mM ADP was 87 and 54%, respectively, and inhibition by 1 mM GDP was 93 and 24%, respectively. rPRS II was 180-fold more sensitive than rPRS I to heat inactivation at 49 degrees C.[1]

References

  1. Expression of rat phosphoribosylpyrophosphate synthetase subunits I and II in Escherichia coli. Isolation and characterization of the recombinant isoforms. Ishijima, S., Kita, K., Ahmad, I., Ishizuka, T., Taira, M., Tatibana, M. J. Biol. Chem. (1991) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Use
 

Editor

Share

Personal info

View

Links

About

Terms

 

WikiGenes - Universities