Rowles J, Slaughter C, Moomaw C, Hsu J, Cobb M H
University of Texas Southwestern Medical Center, Department of Pharmacology, Dallas 75235-9041.
Proc Natl Acad Sci U S A. 1991 Nov 1;88(21):9548-52. doi: 10.1073/pnas.88.21.9548.
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-delta) 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-alpha) and two homologous enzymes (CKI-beta and CKI-gamma) 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.
我们已从牛胸腺中纯化酪蛋白激酶I(CKI)超过6000倍,并对占该酶一级序列近25%的7个胰蛋白酶肽段进行了测序。通过聚合酶链反应(PCR),分离出了编码CKI和一种相关酶(CKI-δ)的部分互补DNA(cDNA)。还检测到一种可能对应于CKI可变剪接形式的产物。CKI的PCR产物用于探测牛脑cDNA文库,从中鉴定出了与CKI(CKI-α)以及两种同源酶(CKI-β和CKI-γ)对应的cDNA。存在至少四种CKI样酶这一发现表明,组织或细胞提取物中的CKI活性可能由多种相关但不同的蛋白激酶组成。这组酶与任何其他已知的蛋白激酶都不相似,因此可能代表蛋白激酶家族的一个新分支。