Possible Interaction: Alkaline Phosphatase and Phenylalanine

“The ALP in all the groups was thermostable (65°C for 15 min) and was inhibited by L-phenylalanine , but no inhibition was seen with L-homoarginine in patients group only.”

“In the presence of L-phenylalanine , an ALP inhibitor, a strong decrease in fluorescence recovery was observed.”

“1) Optimum pH of the enzyme was essentially identical through the species of the animals but the inhibition of L-phenylalanine was clearly demonstrable with human ALP but little with that of other animals.”

“We found that, unlike the BLK‐ALP of … cell line, the activity of U‐2 OS ALP was thermostable, unaffected by … levamisole, but inhibited by L‐phenylalanine ; these properties are characteristic of the placental and/or placental‐like (… ALP) isoenzymes which are 98% homologous at the amino acid level.”

“In the fourth system the proportions of total ALP inhibited by phenylalanine and homoarginine, respectively, were assessed.”

“However, we found that at pH 10.0, with p-nitrophenyl phosphate as the substrate, L-phenylalanine obviously inhibits the alkaline phosphatase isoenzyme from human placenta, whereas there is little if any inhibition of the isoenzyme from human intestine.”

“The alkaline phosphatases of liver and bone are only minimally inhibited by L-phenylalanine , whereas intestinal and placental alkaline phosphatase and Regan isoenzyme are inhibited 77 to 79%.”

“Although biochemical assays suggested thatl-phenylalanine inhibited both alkaline phosphatase and HCO3−-activated ATPase, cytochemical studies indicated that there was marked inhibition of alkaline phosphatase revealing a specific HCO3−-activated ATPase on the inner aspect of the microvillus membrane.”

“Inhibition of alkaline phosphatase with L-phenylalanine , to the same extent as with Ca2+, increased MFP absorption with respect to controls but to a lower degree than with Ca2+.”

“This alkaline phosphatase effect on desensitization was inhibited by L‐phenylalanine.”