Protein Synthesis Essay

Alkaline phosphatases (ALP), members of the phosphomonoesterase family, hydrolyze the oxygen-phosphorus bond of organophosphates using metal ions to release an inorganic phosphate under alkaline conditions.1,2 These enzymes are dimeric metalloenzymes containing two Zn2+, one Mg2+, and a serine residue in the active site of each monomeric subunit, in both prokaryotes and higher eukaryotes.2,3 Studies have shown that the three divalent cations are essential for enzymatic activity to catalyze the formation of an alcohol and an inorganic phosphate (Figure 1). In E. coli, the zinc ions are positioned to activate the serine and water for nucleophilic attack and ultimate cleavage of the bond, in addition to holding the phosphate moiety of the substrate. The magnesium ion has been suggested to stabilize the transferred phosphoryl group by a water molecule, using a separate mechanism by which the zinc ions function.3

Although ALPs are found widely in nature and function similarly on the biochemical level, there are locational

Coomassie G-250 is doubly protonated in acidic conditions and appears red in color; however, when bound to the basic amino acids of the protein, the dye shifts to the anionic blue form. As the protein and dye interact, an electron is donated to the charged groups within the protein so that the protein structure is disrupted and the hydrophobic pockets are exposed. The sulfonic groups of the dye bind to the amines within the exposed hydrophobic pockets to shift the dye to the anionic blue form. This color change is measured spectroscopically and is a direct correlation to the concentration of protein.10 Consequently, the BSA standard is used for comparison, because the basic and aromatic amino acid compositions are similar between the BSA standard and alkaline