RT Journal Article SR Electronic(1) A1 Waters, M. Fiona A1 Mclennan, Alexander G. A1 Carr, Noel G.YR 1989 T1 Purification and Activity Gel Analysis of Polynucleotide Phosphorylase from the Cyanobacterium Nostoc sp. MAC JF Microbiology, VO 135 IS 7 SP 2045 OP 2054 DO https://doi.org/10.1099/00221287-135-7-2045 PB Microbiology Society, SN 1465-2080, AB 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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-135-7-2045