Purification of a nuclease from human serum

Summary The purification procedure for a nuclease from human serum is described. It includes ammonium sulfate precipitation, chromatography on DEAE-Sephadex and on Sephacryl-S 200, and preparative electrophoresis. The enzyme, purified about 2000-fold, is homogeneous in a sodium dodecyl sulfate electrophoretic system, where it has a mol. wt of 78,000. The pH optimum lies around pH 6.5; it is a sugar-nonspecific endonuclease.Acknowledgment. This work has been supported by a research grant from Stiftung Volkswagenwerk through the Akademie der Wissenschaften und der Literatur, Mainz. We thank Mrs R. Nehrbass and Mrs C. Wolpert for technical assistance.     

Uptake of3H-GABA (γ-aminobutyric acid) and3H-leucine in the pancreatic islets and substantia nigra of the rat

Summary Isolated pancreatic islets and thin slices of substantia nigra (SN) of the rat were incubated in a medium containing³H-GABA or³H-leucine to test the activity of both tissues in the uptake of those substances. Pancreatic islets showed a low uptake of both³H-GABA and³H-leucine, but SN had a high activity in the uptake of³H-GABA, though not for³H-leucine. This suggests that GABA contained at high levels in the pancreatic islets plays some functional role other than in neurotransmission as in the central nervous system (CNS).     

Microheterogeneity of staphylococcal enterotoxin C2

Résumé L'hétérogénéité de l'entérotoxine C₂ d'un staphylocoque par électrophorèse en gel polyacrylamide est reliée à la présence d'isomers de charge différente.

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Acknowledgments. We thankDebbie Jeffrey, Yukio Yano andRobert Gagné for excellent technical assistance.