Les phosphatases des végétaux supérieurs: répartition et action

Biosynthesis of monoterpenes

“…These enzymes may be removed by sucrose-gradient fractionation or inhibited by the addition of fluoride, citrate, molybdate, or other ions. [485][486][487] (g) Nonspecific interactions between proteins that occur in aqueous plant extracts are claimed to cause inactivation of certain plant enzymes during storage at low temperature; this effect is stated to be reduced by the addition of sugar or polyglycols.488 (h) Adsorption of soluble protein on to cell walls or membranes during homogenization. This can be minimized by repeated homogenization and washing of the cell-wall fraction, or by a careful choice of buffer and incorporation of nonaqueous solvents into the extraction medium.…”

Mechanism of Action of the Nonspecific Phosphomonoesterase from Potatoes*

“…p-Nitro-T Xhe mechanism of action of the phosphomonoesterases (orthophosphoric monoester phosphohydrolases, EC 3.1.3.2), which include the specific and nonspecific phosphatases, has been a subject of interest for some time. Phosphomonoesterases have been shown to cleave their substrates at the P-O bond (Schmidt and Laskowski, 1961), and inorganic phosphate, always a product of the reaction, is a competitive inhibitor (Courtois and Lino, 1961). Detailed product-exchange and kinetic studies have led to the postulation of a mechanism for two of the specific phosphatases (Byrne, 1961), but similarly complete data have not been available for any of the nonspecific phosphatases.…”

Longitudinal and Transversal Microgradient of Acid Phosphomonoestherase in Growing and Geostimulated Maize Roots

“…Although acid phosphomonoestherase was early discovered (Suzuki et al, 1906), its biological significance is not yet clear (Courtois and Lino 1961), since it is rather unspecific. In the present paper, using maize apical root segments, the physiological changes of this enzyme were carefully analysed.…”