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Effect of Metal Cations on Aldolase from Leaves of Zea mays L. Seedlings 1
Author(s) -
Clark Ralph B.
Publication year - 1966
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1966.0011183x003600060029x
Subject(s) - aldolase a , divalent , cyanide , pyrophosphate , metal , fructose bisphosphate aldolase , enzyme , nuclear chemistry , zea mays , biochemistry , chemistry , biology , inorganic chemistry , organic chemistry , agronomy
Aldolase prepared from 7‐ to 10‐day‐old Zea mays L. leaves was assayed for its response to metal cations. Monovalent cations at concentrations up to 0.2 M and divalent cations at concentrations up to 0.04 M had no stimulatory effect on aldolase activity. Aldolase was completely inhibited by Zn ++ and Co ++ at 0.04 M, 60% by Fe ++ 20% by Mn ++ , and 0% by Ca ++ or Mg ++ . It was inhibited slightly by NH 4 + above 0.1 M, but not by K + Rb + , Cs + , Li + , or Na + . Cyanide and a,á‐dipyridyl were inhibitory to aldolase above 5 × 10 −3 M, but ethylenediaminetetraacetic acid, 2,3‐dimercapto‐l‐propanol, and pyrophosphate were not. ο‐Phenanthroline inhibited aldolase below as well as above 5 × 10 −3 M . Aldolase was also prepared from corn seedlings grown 14 days in complete, minus‐K, and minus‐Zn nutrient solutions. Aldolase activity was lower in preparations from K‐ and Zn‐deficient plants than in preparations from nondeficient plants. K + and Zn ++ added in vitro to aldolase from K‐ and Zn‐deficient plants did not stimulate the enzyme. The reduced aldolase activity found in mineral‐deficient plants was attributed to reduced protein synthesis rather than to a requirement for metal cations for aldolase activity.