Rapid and reliable identification of “casein kinases TS” in many tissues by means of a new specific and very suitable model substrate
✍ Scribed by Flavio Meggio; Arianna Donella-Deana; Lorenzo A. Pinna
- Book ID
- 102628782
- Publisher
- Elsevier Science
- Year
- 1981
- Tongue
- English
- Weight
- 368 KB
- Volume
- 111
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
The low-molecular-weight soybean antiprotease C-II is specifically phosphorylated by a CAMP-independent protein kinase (Casein kinase TS) much more readily than casein itself. Unlike the routinely used substrates casein and phosvitin, C-II is not affected either by casein kinases S or by the CAMP-dependent protein kinase. It can be successfully employed therefore for the direct and reliable evaluation of casein kinase TS within preparations still contaminated by other protein kinases. Crude preparations of soybean antiproteases can replace C-II as specifically phosphorylatable substrate of casein kinase TS. though displaying a much lower phosphorylation efficiency.
1 The inspection of the amino acid sequences around the phosphorylated residues of naturally occurring phosphoproteins suggests that protein kinases exhibiting the site specificity of casein kinases TS might be responsible for the phosphorylation of several heterogeneous proteins, including, besides casein itself (5), also pepsin (lo), fibrinogen (1 l), and nucleolar nonhistone proteins (12).