title: Purification and characterization of pea chloroplastic phosphoriboisomerase.
abstract: Pea (Pisum sativum L.) chloroplastic phosphoriboisomerase (EC 5.3.1.6) can be purified to apparent homogeneity in less than 2 days time with a 53% yield. Important steps in the purification include heat treatment and pseudoaffinity chromatography on Red H-3BN Sepharose. The purified isomerase has a subunit molecular mass of 26.4 kD. The N-terminal sequence has been determined through 34 residues. pH optima are 7.8 (ribose-5-phosphate) and 7.7 (ribulose-5-phosphate); K(m) values are 0.9 millimolar (ribose-5-phosphate) and 0.6 millimolar (ribulose-5-phosphate). The enzyme is inhibited by erythrose-4-phosphate, sedoheptulosebisphosphate, glyceraldehyde-3-phosphate, and 3-phosphoglycerate at concentrations close to those found in photosynthesizing chloroplasts. Countercurrent phase partitioning experiments indicate that the pea chloroplastic phosphoriboisomerase interacts physically with phosphoribulokinase.
authors: Department of Biological Sciences, University of Illinois at Chicago, Chicago Illinois 60680.
authors: C L
authors: CL
authors: Skrukrud
authors: I M
authors: IM
authors: Gordon
authors: S
authors: S
authors: Dorwin
authors: X H
authors: XH
authors: Yuan
authors: G
authors: G
authors: Johansson
authors: L E
authors: LE
authors: Anderson