title: Human placenta DNA primase: purification of enzyme and analysis of RNA primer synthesis.
abstract: The immunoaffinity purification of human placenta DNA primase devoid of DNA polymerase alpha activity is described. Primase consists of 52 and 59 kDa polypeptides. They form a single protein of 330 kDa under native conditions. The polypeptide structure of primase is believed to be (52 + 59)3. Primase synthesizes the oligoribonucleotides 2-9 monomers long and multimeric oligoribonucleotides of a modal length of about 10 monomers. The following model of RNA primer synthesis is proposed: 1) primase, being in free state or in complex with Pol alpha, forms a protein trimer or another structure that includes several primases; 2) primase synthesizes de novo only the oligonucleotides 2-10 monomers in length; 3) the newly synthesized oligonucleotides dissociate in solution or translocate to either Pol alpha or a neighbouring primase unit to be further elongated with the next 7-10 mononucleotides.
authors.affiliation: Novosibirsk Institute of Bioorganic Chemistry, Siberian Division of the USSR Academy of Sciences, Novosibirsk.
authors.forename: V N
authors.initials: VN
authors.lastname: Podust
authors.forename: O V
authors.initials: OV
authors.lastname: Vladimirova
authors.forename: O I
authors.initials: OI
authors.lastname: Lavrik
mesh_terms: D002846:Chromatography, Affinity; D019915:DNA Primase; D004261:DNA Replication; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008954:Models, Biological; D010920:Placenta / Q000201:enzymology*; D011489:Protein Denaturation; D012313:RNA / Q000096:biosynthesis*; D012316:RNA Nucleotidyltransferases / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: C034477:RNA primers; D012313:RNA; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases