title: Calmodulin-dependent and independent NAD kinase activities from cytoplasmic and chloroplastic fractions of spinach (Spinacia oleracea L.).
abstract: NAD kinase activity has been found in a soluble, cytoplasmic fraction and in the chloroplasts prepared from green spinach leaves. A small amount of both the cytoplasmic and the chloroplastic NAD kinase activities was retained on a calmodulin-Sepharose affinity column. The cytoplasmic NAD kinase eluted from the affinity column was found to be enhanced by calmodulin in a Ca(2+)-dependent manner. The chloroplastic enzyme which is located exclusively in the stroma and not in the envelope and thylakoid fractions was not affected by Ca(2+) and calmodulin. The stromal fraction of purified chloroplasts contained only a negligible amount of calmodulin, most probably due to cytoplasmic contamination. Based on these data, two different mechanisms for the light-dependent modulation of spinach NAD kinase activity are suggested.
authors.affiliation: Laboratoire de Physiologie Végétale, Université de Genève, 3 Place de l'Université, Geneva, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Simon
authors.forename: P
authors.initials: P
authors.lastname: Dieter
authors.forename: M
authors.initials: M
authors.lastname: Bonzon
authors.forename: H
authors.initials: H
authors.lastname: Greppin
authors.forename: D
authors.initials: D
authors.lastname: Marmé