Kinetin-induced Changes in δ-Aminolevulinic Acid Dehydratase of Tobacco Callus

Abstract

Kinetin-induced changes in dry weight, soluble protein content, 6-aminolevulinic acid dehydratase activity, and chlorophyll content of two clones of Nicotiana tabacum L. callus were studied. Kinetin brought about a marked increase in the 5-aminolevulinic acid dehydratase activity of nongreen tissue just before induction of greening. The experimental data suggested a possible induction of specific chloroplast protein(s) during the kinetin-induced greening of nongreen tobacco tissue. Kinetin caused a decline in the 5-aminolevulinic acid dehydratase activity and chlorophyll content of the green callus used in the present study.Although there have been a number of investigations concerning the biochemical events during greening of higher plant tissues (1,3,7,(8)(9)(10)(11)(12)20), the accompanying changes in enzymes for Chl synthesis are not well studied. The little work done on the changes in Chl synthesis enzymes has been confined to light-induced greening (22-25, 28, 29, 31 Chlorophyll synthesis was studied on a medium containing salts and vitamins of modified (13) Murashige and Skoog's medium supplemented with 6% sucrose and 2 mg/l of kinetin. This medium has been referred to as CIM in this paper. Media were gelled with 0.8% agar. The pH was adjusted to 5.8 before the

Activity of 5-Aminolevulinic Acid Dehydratase Declines during Tomato Fruit Development and Ripening

“…Schneider (1970) found a broad pH optimum of 7.9 to 9.0 for ALAD from crude leaf extract of spinach (Spinacea oleracea L.) and observed a pH optimum of 8.2 for the highly purified enzyme. A broad pH optimum of 9.2 to 9.5 has been reported for ALAD from crude extracts of green callus of tobacco (Nicotiana tabacum L.) (Kaul and Sabharwal, 1974). Nandi and Waygood (1967) measured a K m of 1.0 mM for ALA in leaves of wheat (Triticum aestivum L.), and Kaul and Sabharwal (1974) reported a Km of 0.46 mM for ALA.…”

“…The mixtures were microcentrifuged at 16,000× g (14,000 rpm) for 8 min to precipitate proteins, and 500 µl of supernatant was mixed 1 : 1 with modified Ehrlich's reagent (Mauzerall and Granick, 1956). After 15 rein, absorbance of the mixture at 553 nm was determined against a reaction mixture blank that did not contain ALA. PBG concentration was calculated by using a molar extinction coefficient of 6.2 × 10 4 per M per cm (Kaul and Sabharwal, 1974). The effect of pH on ALAD activity was determined by varying the pH of the Tris-HCl reaction buffer.…”

Influence of Packaging Materials and Size on Shelf Life and Quality of White Button Mushroom during Storage

“…In all the treatments of mushroom stored at ambient and low temperature, the polyphenol oxidase activity (PPO) was assayed by the method as described by Kaul and Farooq (1994). Five g mushroom was homogenized in 10 ml of cold 0.2 M tris -HCl buffer (pH = 7.5) containing 0.1 M each of cystein and EDTA.…”

Selective Cleavage of Cbz-Protected Amines

“…All substrates, many of which bear pendant functionality, reacted efficiently to afford high isolated yields of the corresponding N−H materials. Noteworthy cases include a trifluoromethylated pyrazole (entry 2) used in the preparation of modified ferrocenyl ligands as catalysts for asymmetric synthesis 7 and a kinetin derivative (last entry), the parent system being known to cause rapid cell division in plants, while kinetin riboside is a known antitumor antiviral agent 1 Cleavage of N -Cbz Carbamates Using Ni(0) Catalysis a Isolated, chromatographically purified material.…”