The stability to pH and denaturing agents of crystalline leutine aminopeptidase (bovine lens) (EC 3.4.1.1) is reported. The native enzyme exhibited a molecular weight of 327,000. In 7 M urea below pH 3 and in 23.7 M guanidinium chloride below pH 8.5, both leucine aminopeptidase and its reduced and carboxamidomethylated derivative exhibited a molecular weight on equilibrium centrifugation of 54,...

Peritoneal macrophages from mice infected with Bacille Calmette-Guérin (BCG) and from normal mice were examined for their effects in vitro on thymidine uptake by 10 murine lymphomas, a murine fibroblast line, and a guinea pig hepatoma. Only the murine fibroblast line showed growth inhibition in the presence of BCG macrophages. For the majority of tumors, normal macrophages were profoundly stimu...

1. A new method has been developed for the preparation in good yield of highly purified Azotobacter vinelandii polynucleotide phosphorylase in its reduced form. 2. Aging or digestion with trypsin causes the enzyme to develop a primer requirement that is not eliminated by beta-mercaptoethanol. 3. The development of a primer requirement is accompanied by marked changes of the electrophoretic mobi...

Isolated alpha-, beta-, and gamma-crystallins from young rat lenses were incubated in solution for 16 hr with 3-hydroxykynurenine under ultraviolet (366 nm) light. Controls included: incubation without light, without kynurenine, and with 2-mercaptoethanol. These procedures generated several chromophors (with absorption maxima or shoulders at 340, 370, and 470 nm) and fluorophors (with excitatio...

The stability to pH and denaturing agents of crystalline leutine aminopeptidase (bovine lens) (EC 3.4.1.1) is reported. The native enzyme exhibited a molecular weight of 327,000. In 7 M urea below pH 3 and in 23.7 M guanidinium chloride below pH 8.5, both leucine aminopeptidase and its reduced and carboxamidomethylated derivative exhibited a molecular weight on equilibrium centrifugation of 54,...

After immunization with either live or heat-killed Salmonella typhimurium, mice responded with an extremely rapid production of bactericidal antibody which was correlated with the appearance of immunity to a heavy challenge dose (100 ld(50)) of the virulent bacteria. Inactivation of sera with mercaptoethanol along with Sephadex fractionation indicated that the observed bactericidal activity was...

Previous studies have reported enhanced vigilance for threat-related information in response to acute stress. While it is known that acute stress modulates sensory systems in humans, its impact on olfaction and the olfactory detection of potential threats is less clear. Two psychophysical experiments examined, if acute stress lowers the detection threshold for foul-smelling 2-mercaptoethanol. P...

Experiments are reported concerning both natural and specific antibody production in endotoxin-treated rats.

A modified rapid slide agglutination test for the presumptive identification of Brucella canis infection in dogs has been developed. The method required mixing 0.1 ml of canine serum with 0.1 ml of 0.2 M 2-mercaptoethanol solution. Equal volumes (0.05 ml) of the treated serum and the B. canis plate antigen were mixed. Agglutination results were read within 2 min. Clinical studies showed 100% ag...