Jan 23, 1976

Partial purification and properties of a chromatin-associated phosphoprotein kinase from rat liver nuclei

Biochimica Et Biophysica Acta
L E Rikans, R W Ruddon

Abstract

A phosphoprotein kinase (EC 2.7.1.37) KIVb, from rat liver nuclei, was purified 75-fold by phosphocellulose chromatography and gel filtration on Sephadex G-200. The enzyme, which has an apparent molecular weight of 55 000, phosphorylates casein and chromatin-bound nonhistone proteins more readily than histones or ribosomal proteins. It exhibits an absolute requirement for divalent cation with optimum activity at 15--20 mM Mg2+. Maximal kinase activity is achieved at 100 mM NaCl. The pH vs. activity curve is biphasic with optima at pH 6.5 and pH 8.0. The Km value for casein is 280 mug/ml and the Km for ATP is 6-10(-6) M. Kinase KIVb phosphorylates numerous nonhistone nuclear proteins as shown by electrophoretic analysis. The addition of kinase KIVb to reaction mixtures containing nonhistone proteins results in the phosphorylation of a spectrum of polypeptides similar to those that are phosphorylated by endogenous nuclear kinases. Nonhistone proteins bound to chromatin appear to be better substrates for KIVb than nonhistones dissociated from chromatin. A comparison of nuclear phosphoproteins phosphorylated either in the intact animal or in vitro (by the addition of kinase KIVb) indicates some differences and some similarities in ...Continue Reading

Mentioned in this Paper

Casein allergenic extract
Sephadex G 200
Cations, Divalent
Caseins
Nuclear Proteins
Ribosomal Proteins
LIM Domain Kinase 1
Chromatography
Protein Phosphorylation
Cell Nucleus

About this Paper

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

Head And Neck Squamous Cell Carcinoma

Squamous cell carcinomas account for >90% of all tumors in the head and neck region. Head and neck squamous cell carcinoma incidence has increased dramatically recently with little improvement in patient outcomes. Here is the latest research on this aggressive malignancy.

Signaling in Adult Neurogenesis

Neural stem cells play a critical role in the production of neuronal cells in neurogenesis is of great importance. Of interest is the role signalling mechanisms in adult neurogenesis. Discover the latest research on signalling in adult neurogenesis.

Psychiatric Chronotherapy

Psychiatric Chronotherapy considers the circadian rhythm as a major factor for optimizing therapeutic efficacy of psychiatric interventions. Discover the latest research on Psychiatric Chronotherapy here.

Bone Marrow Neoplasms

Bone Marrow Neoplasms are cancers that occur in the bone marrow. Discover the latest research on Bone Marrow Neoplasms here.

IGA Glomerulonephritis

IgA glomerulonephritis is a chronic form of glomerulonephritis characterized by deposits of predominantly Iimmunoglobin A in the mesangial area. Discover the latest research on IgA glomerulonephritis here.

Cryogenic Electron Microscopy

Cryogenic electron microscopy (Cryo-EM) allows the determination of biological macromolecules and their assemblies at a near-atomic resolution. Here is the latest research.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.