Potassium requirement of pyruvate kinase extracted from leaves of halophytes.

Pyruvate kinase enzymes were partially purified from leaves of halophytes, Atriplex gmelini C. A. Mey., Chenopodium acuminatum Wild, and Spergularia salina J. et C. Presl., grown hydroponically in the presence of 250 mM NaCl in a greenhouse, to determine their Km values for potassium. The values were all ca 10−3M, as also reported for the glycophyte enzymes. However, the Km values were reduced by 60 to 70% by the addition of betaine to a concentration of 1 M. [ABSTRACT FROM AUTHOR]