%0 Journal Article %A Waters, M. Fiona %A Mclennan, Alexander G. %A Carr, Noel G. %T Purification and Activity Gel Analysis of Polynucleotide Phosphorylase from the Cyanobacterium Nostoc sp. MAC %D 1989 %J Microbiology, %V 135 %N 7 %P 2045-2054 %@ 1465-2080 %R https://doi.org/10.1099/00221287-135-7-2045 %I Microbiology Society, %X 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. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-135-7-2045