Bismuth citrate in the quantification of inorganic phosphate and its utility in the determination of membrane-bound phosphatases.
This paper describes a rapid and sensitive method to determine inorganic phosphate, even in the presence of labile organic phosphate compounds and large quantities of proteins. The method eliminates the use of sodium arsenite, a highly toxic compound, substituting bismuth citrate for it to stabilize the phosphomolybdic acid complex formed during the interaction of inorganic phosphate and molybdate reduced by ascorbic acid. This method has also been adapted to microplates and has been used to determine the activities of Na/K ATPase and alkaline phosphatase of intestinal basolateral and luminal plasma membranes.
Cariani
L
L
Lab. Fisiologi;a Gastrointestinal, Centro de Biofísica y Bioquímica, Caracas 1020-A, Venezuela.
Thomas
L
L
Brito
J
J
del Castillo
J R
JR
D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D018053:Arsenites / Q000737:chemistry / Q000633:toxicity; D001205:Ascorbic Acid / Q000737:chemistry; D002021:Buffers; D002462:Cell Membrane / Q000201:enzymology*; D020895:Enterocytes / Q000201:enzymology*; D007413:Intestinal Mucosa / Q000201:enzymology; D016014:Linear Models; D008982:Molybdenum / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000032:analysis; D010710:Phosphates / Q000032:analysis* / Q000592:standards; D010756:Phosphoric Acids / Q000737:chemistry; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis*; D017670:Sodium Compounds / Q000737:chemistry / Q000633:toxicity; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D013053:Spectrophotometry
D018053:Arsenites; D002021:Buffers; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D010710:Phosphates; D010756:Phosphoric Acids; D017670:Sodium Compounds; C017947:sodium arsenite; D008982:Molybdenum; D000469:Alkaline Phosphatase; D010744:Phosphoric Monoester Hydrolases; D000254:Sodium-Potassium-Exchanging ATPase; C002791:bismuth tripotassium dicitrate; D001205:Ascorbic Acid; C003125:phosphomolybdic acid