Skeletal Alkaline Phosphatase

Skeletal alkaline phosphatase activity in serum.

Turnover rate of skeletal alkaline phosphatase in humans.

Two patients with Paget's disease of bone were subjected to plasmapheresis. Alkaline phosphatase activities of serum declined sharply, but returned to preplasmapheresis values within eight to 10 days. The biological half-life of circulating skeletal alkaline phosphatase, as calculated from these experiments, is between 1.12 and 2.15 days.

Phosphotyrosyl-specific protein phosphatase activity of a bovine skeletal acid phosphatase isoenzyme. Comparison with the phosphotyrosyl protein phosphatase activity of skeletal alkaline phosphatase.

A partially purified bovine cortical bone acid phosphatase, which shared similar characteristics with a class of acid phosphatase known as tartrate-resistant acid phosphatase, was found to dephosphorylate phosphotyrosine and phosphotyrosyl proteins, with little activity toward other phosphoamino acids or phosphoseryl histones. The pH optimum was about 5.5 with p-nitrophenyl phosphate as substra...

Fluoride and Alkaline Phosphatase

Since serum alkaline phosphatase increases in fluoride therapy for osteoporosis, it is generally accepted that fluoride stimulates bone formation. However, histochemical studies have shown that alkaline phosphatase is also increased in resorbing osteocytes. Fluoride is toxic to metabolically active bone cells, alkaline phosphatase is released, and serum alkaline phosphatase increases. We propos...

Chicken Intestinal Alkaline Phosphatase

Purified chicken intestinal alkaline phosphatase is active at pH 8 to 9, but becomes rapidly inactivated with change of pH to 6 or less. Also, a solution of the inactivated enzyme at pH 4.5 rapidly regains its activity at pH 8. In the range of pH 6 to 8 a solution of purified alkaline phosphatase consists of a mixture of active and inactive enzyme in equilibrium with each other. The rate of ina...