title: In vivo nitrate reductase activity in dark- and light-grown sugarcane callus.
abstract: The in vivo nitrate reductase activity in 8 day old dark-grown sugarcane callus was over three fold that of the light-grown callus. NADH (0.3 mM) in the reaction system, increased the in vivo nitrate reductase activity by more than two fold both in the dark- and the light-grown callus tissues. The NADH dependence of nitrate reductase activity followed Michaelian kinetics. The apparent Km values for NADH were 0.083 mM and 0.20 mM, respectively, for the dark- and the light-grown callus. In vivo nitrate reductase activity in green sugarcane leaves (field grown) was unaffected by NADH in the reaction system. Under the standard conditions of assay up to 60% of the NADH penetrated into the sugarcane callus within 2 min. No penetration of NADH into the sugarcane leaf discs was, however, recorded under identical conditions.
authors.affiliation: Biochemistry Division, National Chemical Laboratory, 411 008, Poona, India.
authors.forename: B M
authors.initials: BM
authors.lastname: Khan
authors.forename: U N
authors.initials: UN
authors.lastname: Dwivedi
authors.forename: S K
authors.initials: SK
authors.lastname: Rawal
authors.forename: A F
authors.initials: AF
authors.lastname: Mascarenhas