English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Protein kinase activity that is independent of cAMP has been reported to exist on the surface of intact HeLa cells. Here we report that the protein kinase activity can be released by the use of casein or phosvitin within a short period of time. The discharge of the enzyme occurs from intact cells since (i) the cells do not release intracellular material and (ii) the cultures continue to grow within any morphological alteration. As shown with phosvitin, the release of protein kinase depends on substrate concentration, incubation time, and temperature. The degree of inducible release or surface protein kinase is inversely related to cell density. Four incubations with phosvitin (1 mg/ml) are sufficient to liberate most of the enzyme, thus greatly reducing the capacity of the cells to phosphorylate cellular substrates at the surface. Within approximately 24 hr after protein kinase removal, cultures have restored their surface protein kinase. Cultured cells of different origin (rat liver, mouse cerebellum, and human lung) exhibited phosvitin-induced protein kinase release from intact cells. The possible significance of these observations with respect to extracellular protein phosphorylation is discussed.

Substrate-effected release of surface-located protein kinase from intact cells.