title: Isolation and Partial Purification of Two Types of Nuclear Tyrosine Protein Kinase from Rat Liver.
abstract: Nuclear tyrosine protein kinase (n-TPK) plays an important role in the regulation of cell cycle and gene transcription. In the present investigation, two types of n-TPK isozyme, n-TPK I and n-TPK II were isolated from the nuclear extract of rat liver by using DEAE-Sepharose CL-6B ion-exchange column chromatography. The two isozymes were further partially purified on heparin affinity column and Sephadex G-100 to 30 and 25 folds respectively. The specific activities of n-TPK I and n-TPK II were 1 638 and 1 360 pmol/(min.mg protein) respectively. By means of Sephadex G-100 chromatography and autoradiography of the autophosphorylated n-TPK after [32P]-ATP labeling and SDS-PAGE, the molecular weight of n-TPK I and n-TPK II were determined to be 76 kD and 59 kD respectively. Both n-TPK isozymes are monomers.
authors.affiliation: Key Laboratory of Glycoconjugate Research, Ministry of Public Health, Department of Biochemistry, Shanghai Medical University, Shanghai 200032, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Hui-Li
authors.initials: HL
authors.lastname: Chen