Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have purified to homogeneity the primer recognition proteins (PRP) from human HeLa cells. PRP is associated with DNA polymerase alpha complex in HeLa cells. Purified PRP is free of DNA polymerases alpha, beta, and delta, deoxyribonuclease, DNA primase, ATPase, topoisomerase, and DNA ligase activities. The protein structure of the PRP was defined by sodium dodecyl sulfate gel electrophoresis, which revealed two polypeptides of 36,000 Da (PRP 1) and 41,000 Da (PRP 2). The two polypeptides are associated in a complex in the native state. The Stokes radius of the PRP complex by gel filtration is 40.5 A and the sedimentation coefficient in glycerol gradients is 5.7 S. Purified PRP, which exhibits no DNA polymerase activity, completely restores the activity of DNA polymerase alpha on templates with low primer to template ratios such as heat-denaturated DNA, poly(dA)-oligo(dT), and singly primed M13 single-stranded DNA. Experiments using various amounts of PRP, DNA polymerase alpha, and DNA indicate that a concentration dependence exists between these components in the DNA replication process. Amino acid composition analysis indicates that the PRP is rich in hydrophobic amino acids.
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PMID:Purification and characterization of primer recognition proteins from HeLa cells. 236 57

Phosphorylation is a major post-translational regulatory mechanism and plays a key role in transduction of mitogenic signals in cell proliferation. The role of phosphorylation and dephosphorylation in regulating the activities of a multiprotein DNA polymerase alpha complex was examined. Treatment of the HeLa cell multiprotein DNA polymerase alpha with calf intestinal alkaline phosphatase resulted in the inactivation of DNA polymerase alpha and DNA primase but had no effect on deoxyribonuclease- and primer-recognition proteins. A protein kinase co-purified with the multiprotein DNA polymerase alpha and was partially purified from HeLa cells. The partially purified kinase was active in phosphorylating dephosphorylated polymerase alpha and used casein and histones as exogenous substrates. This study demonstrates that phosphorylation-dephosphorylation may have modulated the activities of DNA replicative enzymes and suggests a role for specific phosphatases and kinases in this process.
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PMID:Phosphorylation of HeLa cell multiprotein DNA polymerase alpha complex: impact on activity and partial purification of the associated kinase. 256 5