Purification and Activity Gel Analysis of Polynucleotide Phosphorylase from the Cyanobacterium Nostoc sp. MAC Waters, M. Fiona and Mclennan, Alexander G. and Carr, Noel G.,, 135, 2045-2054 (1989), doi = https://doi.org/10.1099/00221287-135-7-2045, publicationName = Microbiology Society, issn = 1350-0872, abstract= Polynucleotide phosphorylase has been purified from the cyanobacterium Nostoc sp. MAC. The enzyme requires a divalent cation such as Mg2+, has a pH optimum of 10·5 and catalyses the polymerization of ADP into polynucleotide in a primer-independent reaction at a rate of 2 mol min−1 (mg protein)−1. It has an apparent native M r of 215000–240000. Non-denaturing polyacrylamide activity gels reveal a heterogeneous pattern of active bands similar to those previously observed with the corresponding enzyme from Micrococcus luteus, while SDS-denaturing activity gels reveal a single band of activity of M r 91000 in both crude extracts and the most highly purified fraction. Activity has also been demonstrated in a cetyltrimethyl-ammonium bromide non-denaturing activity gel. By analogy with other known polynucleotide phosphorylases, the Nostoc enzyme is probably a trimer of the 91000-M r subunit., language=, type=