title: Synthesis and degradation of nitrate reductase during the cell cycle of Chlorella sorokiniana.
abstract: Studies on the diurnal variations of nitrate reductase (NR) activity during the life cycle of synchronized Chlorella sorokiniana cells grown with a 7:5 light-dark cycle showed that the NADH:NR activity, as well as the NR partial activities NADH:cytochrome c reductase and reduced methyl viologen:NR, closely paralleled the appearance and disappearance of NR protein as shown by sodium dodecyl sulfate gel electrophoresis and immunoblots.  Results of pulse-labeling experiments with [35S]methionine further confirmed that diurnal variations of the enzyme activities can be entirely accounted for by the concomitant synthesis and degradation of the NR protein.
authors.affiliation: Department of Food Science and Technology, University of California, Davis 95616, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Velasco
authors.forename: R
authors.initials: R
authors.lastname: Tischner
authors.forename: R C
authors.initials: RC
authors.lastname: Huffaker
authors.forename: J R
authors.initials: JR
authors.lastname: Whitaker
mesh_terms: D002453:Cell Cycle / Q000502:physiology; D002708:Chlorella / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism; D006540:Herbicides / Q000378:metabolism; D008027:Light; D009243:NAD / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D009565:Nitrate Reductases / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D010269:Paraquat / Q000378:metabolism; D017440:Photoperiod; D010940:Plant Proteins / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D006540:Herbicides; D010940:Plant Proteins; D009243:NAD; D009245:NADH Dehydrogenase; D009565:Nitrate Reductases; D010269:Paraquat