Phosphatase, Alkaline from Escherichia coli

Alkaline phosphatase (ALP) of E.coli is a member of an enzyme group that possesses intragenic complementation.

The enzyme from Sigma has been used to develop a synthetic nanopore membrane. This membrane mimics protein channels that are regulated by phosphorylation/dephosphorylation and uses an aligned array of carbon nanotubes (CNTs) impregnated in a polystyrene matrix.

Alkaline phosphatase is used for conjugation to antibodies and other proteins for ELISA, Western blotting, and histochemical detection. It may be used for protein labeling when high sensitivity is required. Product P5931 has been used during immunoblots to treat cell membranes prior to Tau1 incubation.

Alkaline phosphatase, from Escherichia coli, is a dimeric, non-glycosylated protein which mainly reside in the periplasmic space. Three known isoforms exist. The enzyme requires zinc, and is activated by magnesium. E. coli akaline phosphatase has a broad specificity for phosphate esters.

The enzyme is a phosphohydrolase having an optimal pH of 10 in vitro. The actual optimum pH varies depending on the nature and concentration of the substrate, the type of buffer, the phosphate acceptor, and to some extent the nature of the isoenzymes. It catalyzes the hydrolysis of phosphate monoesters such as p-nitrophenyl phosphate, phenyl phosphate, phenolphthalein phosphate, α-glycerol phosphate, β-glycerol phosphate, 2-phosphorylglycerate, triosephosphate, glucose-6-phosphate, glucose 1-phosphate, fructose 1-phosphate, fructose 6-phosphate, adenosine 5-phosphate adenosine 3-phosphate, phosphoenolpyruvate, and β-nicotinamide adenine dinucleotide phosphate. The activity is inhibited by 1,10-phenanthroline monohydrate, diethylenetriaminepentaacetic acid, ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid, and ethylenediaminetetraacetic acid disodium salt dihydrate.

Lyophilized powder containing Tris buffer salts, MgSO₄, and ZnSO₄

Chromatographically purified

One unit will hydrolyze 1.0 μmole of p-nitrophenyl phosphate per min at pH 10.4 at 37 °C.