ABSTRACT
This chapter focuses on cellular deoxyribonucleic acid (DNA) polymerases of higher eukaryotes and only occasional note is made on enzymes of lower eukaryotes. It explores structural and catalytic properties of DNA polymerases and their auxiliary factors and biological characteristics and roles of the polymerases. An α-type DNA polymerase was the first eukaryotic DNA polymerase to be partially purified and characterized. Purification and characterization of DNA polymerases-α have been complicated by their multiplicity of forms and diverse properties even within one cell type. The catalytic properties of α-polymerase are defined, therefore, by its interaction with template, primer, deoxyribonucleoside triphosphate substrates, and divalent cation activator. The relative degrees of efficiency with which natural DNA templates and synthetic deoxyribopolymers are copied by α-polymerase depend on source and form of the enzyme and on specific conditions of the reaction. The metal activator enhanced binding of the enzyme to single-stranded DNA and to polypyrimidines but not to polypurines.
