PMID: 43131Nov 1, 1979

Wheat-germ aspartate transcarbamoylase. Purification and cold-lability

The Biochemical Journal
J E GraysonP J Butterworth

Abstract

1. Aspartate transcarbamoylase was purified approx. 3000-fold from wheat (Triticum vulgare) germ in 15-20% yield. The product has a specific activity of 14 mumol/min per mg of protein and is approx. 90% pure. The purification scheme includes the use of biospecific "imphilyte" chromatography as described by Yon [Biochem.J.(1977) 161, 233-237]. The enzyme was passed successively through columns of CPAD [N-(3-carboxypropionyl)aminodecyl]-Sepharose in the absence and presence respectively of the ligands UMP and L-aspartate. In the second passage the enzyme was specifically displaced away from impurities with which it co-migrated in the first passage. These two steps contributed a factor of 80 to the overall purification. 2. The enzyme is slowly inactivated on dilution at 0 degrees C and pH 7.0, the inactivation being partially reversible. A detailed investigation of the temperature- and pH-dependence of the cold-inactivation suggested that it was initiated by the perturbation of the pKa values of groups with a moderately high and positive heat of ionization, which were tentatively identified as histidine residues. These findings support a new concept of cold-lability proposed by Bock, Gilbert & Frieden [Biochem. Biophys. Res. Commu...Continue Reading

References

Dec 1, 1993·FEMS Microbiology Letters·Margaret Shepherdson, Donald McPhail
Jan 6, 2006·Archives of Microbiology·Donald McPhail, Margaret Shepherdson

Related Concepts

Cold Temperature
Aspartic Acid, Magnesium-Potassium (2:1:2) Salt
Pentosuria
Uridine Monophosphate
Factor V Deficiency
Ion-Exchange Chromatography Procedure
Hydrogen-Ion Concentration
Ni(II)-Aspartate Transcarbamoylase

Related Feeds

Blood Clotting Disorders

Thrombophilia includes conditions with increased tendency for excessive blood clotting. Blood clotting occurs when the body has insufficient amounts of specialized proteins that make blood clot and stop bleeding. Here is the latest research on blood clotting disorders.