1zpg: Difference between revisions

[[Image:1zpg.gif|left|200px]]<br /><applet load="1zpg" size="350" color="white" frame="true" align="right" spinBox="true"  

Rat liver arginase (arginase I) is potently inactivated by diethyl pyrocarbonate, with a second-order rate constant of 113M(-1)s(-1) for the inactivation process at pH 7.0, 25 degrees C. Partial protection from inactivation is provided by the product of the reaction, l-ornithine, while nearly complete protection is afforded by the inhibitor pair, l-ornithine and borate. The role of H141 has been probed by mutagenesis, chemical modulation, and X-ray diffraction. The hyper-reactivity of H141 towards diethyl pyrocarbonate can be explained by its proximity to E277. A proton shuttling role for H141 is supported by its conformational mobility observed among the known arginase structures. H141 is proposed to serve as an acid/base catalyst, deprotonating the metal-bridging water molecule to generate the metal-bridging hydroxide nucleophile, and by protonating the amino group of the product to facilitate its departure.

1ZPG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=MN:'>MN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Arginase Arginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.3.1 3.5.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZPG OCA].  

[[Category: Ash, D E.]]

[[Category: Christianson, D W.]]

[[Category: Colleluori, D M.]]

[[Category: Cox, J D.]]

[[Category: Emig, F A.]]

[[Category: Reczkowski, R S.]]

[[Category: Scolnick, L R.]]

[[Category: Viola, R E.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:17:49 2008''