A fraction containing capillaries and rich in gamma-glutamyl transpeptidase was isolated from homogenates of bovine brain cortex by density gradient centrifugation. The enzyme was localized in the endothelial cells by a histochemical procedure. gamma-Glutantyl transpeptidase may function in the transfer of some amino acids across the blood-brain barrier.

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Staphylococcal alpha-toxin induces the release of previously sequestered anions or glucose from artificial phospholipid spherules, an effect abolished by specific antitoxin. Alphatoxin resembles streptolysin S in releasing anions or glucose from spherules prepared without cholesterol, and can be distinguished from the membrane-active polyene amphotericin B, which preferentially disrupts spherules containing cholesterol. It may affect biological structures by a similiar interaction with membrane phospholipids.

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