1. A method for the preparation of brush border from rabbit kidneys is described. Contamination by other organelles was checked by electron microscopy and by the assay of marker enzymes and was low. 2. Seven enzymes, all hydrolases, were substantially enriched in the brush-border preparation and are considered to be primarily located in this structure. They are: alkaline phosphatase, maltase, t...

The hydrolase aminopeptidase A is an important regulator of the renin-angiotensin system, since it inactivates its most vasoactive component angiotensin II (Ang II). A single i.v. injection of a monoclonal antibody against mouse aminopeptidase A (ASD-4) induces a membranous-like glomerulonephritis in mice, characterized by an acute albuminuria, that is not dependent on complement, the coagulati...

Porcine epidemic diarrhea coronavirus (PEDV) has significantly damaged America's pork industry. Here we investigate the receptor usage and cell entry of PEDV. PEDV recognizes protein receptor aminopeptidase N from pig and human and sugar coreceptor N-acetylneuraminic acid. Moreover, PEDV infects cells from pig, human, monkey, and bat. These results support the idea of bats as an evolutionary or...

Inactivation of Pseudomonas aeruginosa phpA, encoding a putative leucine aminopeptidase, results in increased transcription of algD. The homologous protein in Escherichia coli, PepA, is multifunctional, possessing independent aminopeptidase and DNA-binding activities. Here we provide in vitro evidence that PhpA is an aminopeptidase and show that this activity is the relevant property with regar...

Mammalian zinc ectopeptidases play important roles in turning off neural and hormonal peptide signals at the cell surface, notably those processing sensory information. We report here the discovery of a previously uncharacterized physiological inhibitor of enkephalin-inactivating zinc ectopeptidases in humans, which we have named Opiorphin. It is a QRFSR peptide that inhibits two enkephalin-cat...

The enzymatic response of a natural deep-sea microbial community to input of organic matter was investigated by substrate enrichment experiments. Sediments from the BIOTRANS area at 47"N 20°W in the NE Atlantic (4500 m depth) were supplied with particulate and dissolved organic matter from stenhzed net plankton and incubated under in situ pressure and temperature. Changes in the potential hydro...

become new drugs for cancer treatment, not as biological response modifiers (BRM), but as anti-cancer chemicals exerting direct suppressive action on the growth or metastasis of certain cancers. Thus, the specific inhibition ofAP-N could be a new approach to suppress the growth or metastasis of cancer. During the screening for new inhibitors of aminopeptidase N, we obtained new substances MR-38...

To characterize aspartyl aminopeptidase from Aspergillus oryzae, the recombinant enzyme was expressed in Escherichia coli. The enzyme cleaves N-terminal acidic amino acids. About 30% activity was retained in 20% NaCl. Digestion of defatted soybean by the enzyme resulted in an increase in the glutamic acid content, suggesting that the enzyme is potentially responsible for the release of glutamic...