Purification of casein kinase I and isolation of cDNAs encoding multiple casein kinase I-like enzymes

Joie Rowles, Clive Slaughter, Carolyn Moomaw, Joan Hsu, Melanie H. Cobb

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We have purified casein kinase I (CKI) over 6000-fold from bovine thymus and have sequenced seven tryptic peptides that account for nearly 25% of the primary sequence of the enzyme. By using PCR, partial cDNAs encoding CKI and a related enzyme (CKI-δ) were isolated. A product that may correspond to an alternatively spliced form of CKI was also detected. The CKI PCR product was used to probe a bovine brain cDNA library from which cDNAs corresponding to CKI (CKI-α) and two homologous enzymes (CKI-β and CKI-γ) were identified. The finding that there are at least four CKI-like enzymes suggests that CKI activity in tissues or cell extracts may be composed of multiple related but distinct protein kinases. This group of enzymes is not similar to any other known protein kinases and may, therefore, represent an additional branch of the protein kinase family.

Original languageEnglish (US)
Pages (from-to)9548-9552
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number21
Publication statusPublished - 1991


ASJC Scopus subject areas

  • General
  • Genetics

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