This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Ireland, R. J. Articles by Dennis, D. T. Search for Related Content PubMed PubMed Citation Articles by Ireland, R. J. Articles by Dennis, D. T. Agricola Articles by Ireland, R. J. Articles by Dennis, D. T.

Articles

Isoenzymes of Pyruvate Kinase in Etioplasts and Chloroplasts ¹

^a Department of Biology, Queen's University, Kingston, Ontario K7L 3N6 Canada

Isoenzymes of pyruvate kinase from green leaves of castor bean and etiolated leaves of pea plants have been separated by ion filtration chromatography. One of the isoenzymes is localized in the plastid, whereas the other is in the cytosol. The cytosolic enzyme has a pH optimum from pH 7 to pH 9, and is able to utilize nucleotides other than ADP as the phosphoryl acceptor. The plastid enzyme has a much sharper optimum at pH 8, and is less efficient at using alternative nucleotides. The plastic pyruvate kinase, unlike the cytosolic enzyme, requires the presence of dithiothreitol or 2-mercaptoethanol during isolation and storage to stabilize the activity.