Sonicates of mouse bone marrow-derived mast cells (BMMC) differentiated in vitro and of mouse serosal mast cells differentiated in vivo contained small but approximately equal amounts of aminopeptidase activity, as determined by cleavage of leucine-beta-naphthylamide and resolution of the reaction products by reverse-phase high-performance liquid chromatography. Aminopeptidase activity was exoc...

Bestatin reversibly inhibits Aeromonas aminopeptidase (EC 3.4.11.10) in a process that is remarkable for its unusual degree of time dependence. The binding of bestatin by both Aeromonas aminopeptidase and cytosolic leucine aminopeptidase (EC 3.4.11.1) is slow and tight, with Ki values (determined from rate constants) of 1.8 X 10(-8) and 5.8 X 10(-10) M, respectively. In contrast, microsomal ami...

The conformational profiles for the endogenous peptide Opiorphin and a set of seven analogues exhibiting different inhibitory activities toward human aminopeptidase N (hAPN) and human neprilysin (hNEP) were independently computed to deduce a bioactive conformation that Opiorphin may adopt when binding these two enzymes. The conformational space was thoroughly sampled using an iterative simulate...

The post-translational processing of pig small-intestinal aminopeptidase N (EC 3.4.11.2) was studied in organ-cultured mucosal explants. Exposure of the explants to swainsonine, an inhibitor of Golgi mannosidase II, resulted in the formation of a M,-160000 polypeptide, still sensitive to endo-ffi-N-acetylglucosaminidase H. Swainsonine caused only a moderate inhibition of transport of the enzyme...

The fluorometric method for measuring leucine aminopeptidase (EC 3.4.11.1) activity in biological systems, with L-leucyl--naphthylamide as the substrate [C/in. Chem. 16, 412 (1970)] was critically evaluated and refined. In this enzyme assay system, a few precautions are necessary in determining /3-naphthylamine liberated from the substrate by the enzyme action. In water, tris(hydroxymethyl)amin...

The property of solutions of Triton X-114 to separate into detergent-rich and detergent-poor phases at 30 degrees C has been exploited to investigate the identities of the aminopeptidases in synaptic membrane preparations from pig striatum. When titrated with an antiserum to aminopeptidase N (EC 3.4.11.2), synaptic membranes solubilized with Triton X-100 revealed that this enzyme apparently com...

Eighty-six Nocardia strains isolated from clinical samples in Belgium were identified by 16S rRNA gene sequencing. Eighty-three (96%) strains belonged to only six Nocardia species: N. farcinica (38 [44%]), N. nova (19 [22%]), N. cyriacigeorgica (13 [15%]), N. brasiliensis (6 [6.9%]), N. abscessus (5 [5.8%]), and N. paucivorans (2 [2.3%]). A gallery of nine conventional and enzymatic tests was d...

We describe a colorimetric method for assay of microsomal aminopeptidase (EC 3.4.11.2) activity in serum. We use a new substrate, L-leucyl-3-carboxy-4-hydroxyanilide, p-xylenol as coupler, and sodium metaperiodate as oxidizing reagent. The colored substance formed by the oxidative condensation between p-xylenol and 5-aminosalicylic acid absorbs maximally at 635 nm, and can be directly measured ...