EC 2.7.11.23     
Accepted name: [RNA-polymerase]-subunit kinase
Reaction: ATP + [DNA-directed RNA polymerase] = ADP + phospho-[DNA-directed RNA polymerase]
Other name(s): CTD kinase; STK9
Systematic name: ATP:[DNA-directed RNA polymerase] phosphotransferase
Comments: The enzyme appears to be distinct from other protein kinases. It brings about multiple phosphorylations of the unique C-terminal repeat domain of the largest subunit of eukaryotic DNA-directed RNA polymerase (EC 2.7.7.6). The enzyme does not phosphorylate casein, phosvitin or histone.
References:
1.  Lee, J.M. and Greenleaf, A.L. A protein kinase that phosphorylates the C-terminal repeat domain of the largest subunit of RNA polymerase II. Proc. Natl. Acad. Sci. USA 86 (1989) 3624–3628. [PMID: 2657724]
[EC 2.7.11.23 created 1992 as EC 2.7.1.141, transferred 2005 to EC 2.7.11.23]