Hexosediphosphatase from spinach chloroplasts: purification, crystallization and some properties.

Hexosediphosphatase (D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) has been isolated, purified, and crystallized, from previously isolated spinach chloroplasts. The effects of various anions, cations, and sulfhydryl compounds were tested, and activation by Mg2+, glycine, HCO3-, and sulfhydryl compounds is described. The purified enzyme is very specific for fructose 1,6-diphosphate and does not attack sedoheptulose-1,7-bisphosphate. The S20 value of the enzyme was 7.7, from which the molecular weight of the enzyme was estimated as 140,000.