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The influence of NaCl on Δ 1 ‐pyrroline‐5‐carboxylate reductase in proline‐accumulating cell suspension cultures of Mesembryanthemum nodiflorum and other halophytes
Author(s) -
Treichel Siegfried
Publication year - 1986
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1986.tb02440.x
Subject(s) - proline , cycloheximide , substrate (aquarium) , enzyme , reductase , biochemistry , halophyte , enzyme assay , chemistry , biology , amino acid , protein biosynthesis , salinity , ecology
Pyrroline‐5‐carboxylate (P‐5‐C) reductase (EC 1.5.1.2) was extracted from cell suspension cultures, which proved to be very suitable for investigation of proline accumulation. Proline accumulation in cell suspensions of M. nodiflorum L., as well as P‐5‐C reductase activity and substrate affinity, increased with progressive adaptation to NaCl stress. In vitro NaCl treatment inhibited enzyme activity and decreased substrate affinity, independent of pretreatment of the cells. NaCl concentrations below 100 m M did not inhibit enzyme activity of adapted cells. High substrate concentrations counteracted in vitro NaCl inhibition (up to 200 m M ). Cycloheximide inhibited the increase of P‐5‐C reductase activity, as well as proline accumulation, after NaCl treatment, indicating stress‐induced de novo synthesis of the enzyme. The different reactions of P‐5‐C reductase upon salt treatment are discussed with respect to its possible role in the regulation of proline accumulation.