“Of the 24 agents tested in vitro, 5 (cadmium chloride, cupric chloride, mercuric chloride, mercurous chloride, and zinc chloride) … and NH4Cl by the enzymes by nearly 90% at a concentration of 1 mm; 4 other compounds calcium chloride , cobaltous chloride, cuprous … utilization of l-glutamine and NH4Cl … than 50%.”