February 20, 1963
Dear Dr. Lederberg,
Doctor Horecker requested that I send you some of our alkaline phosphatase preparation.  I have sent under separate cover, 0.4 ml of our crystalline enzyme having an activity of 10,000 mu-M of p-Nitrophenyl phosphate hydrolyzed 1 ml/hr at 28 degrees in 1M TAIS pH 8.0, substrate concentration of 10 to the -3 M.  The crystals are suspended in 61% ammonium sulfate, 0.01 M MgCl2.
I would appreciate it if you would let me know if the sample arrived safely and how it worked in your hands.
Sincerely,
Michael Malamy