ISSN:
1573-4919
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Summary Protein phosphatase, active on non-histone phosphoprotein substrate, was partially purified from rat liver cell nuclei by means of salt extraction, ammoniumsulfate precipitation, DEAE cellulose chromatography, gel filtration and preparative isoelectrofocusing. Rat liver nuclei contain a heterogenous population of different protein phosphatases. All the enzyme fractions eluted from DEAE cellulose are of low molecular weight between 12,000–31,000. The pH 5.5 peak fraction of preparative isoelectrofocusing was characterized in detail. It has a pH optimum of 6.8 using nuclear phosphoprotein substrate. It is inhibited by Na+ at 80mm, and to a lesser extent by K+, activated by Mg2+(5mm) and Mn2+ (1mm). However, the latter is inhibitory at 6mm. The nuclear protein phosphatase is also active on labelled F1 and F2b histones and casein, however, its V is lower on histones and it contains component(s) active specifically on nuclear phosphoprotein substrate but not on casein.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00421292
