Takaaki Aoyagi

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The inhibitory effect of various compounds on the activities of four types of rat sialidase was investigated. 2-Deoxy-2,3-dehydro-N-acetylneuraminic acid andN-acetylneuraminic acid were competitive inhibitors for the sialidases. The former was effective against cytosolic sialidase and intralysosomal sialidase more than two membrane-associated sialidases I(More)
Endogenous calcium-activated, phospholipid-dependent protein kinase phosphorylates pig epidermal protein. Pig epidermis was homogenized and centrifuged at 30,000xg for 30 min. The supernatant was incubated with or without calcium and phospholipid. A 97 kD soluble protein from pig epidermis was phosphorylated in the presence of calcium and(More)
Mannostatin A is a metabolite produced by the microorganism Streptoverticillium verticillus and reported to be a potent competitive inhibitor of rat epididymal alpha-mannosidase. When tested against a number of other arylglycosidases, mannostatin A was inactive toward alpha- and beta-glucosidase and galactosidase as well as beta-mannosidase, but it was a(More)
Lactoyl-pepstatin (an acylated tetrapeptide) is much more readily soluble in aqueous media than the more common isovaleryl- and acetyl-pepstatins (acylated pentapeptides). However, the K1 value for inhibition of cathepsin D by lactoyl-pepstatin at pH 3.5 is approx. 10(-7) M, some two to three orders of magnitude weaker than has been obtained previously for(More)
Adenosine deaminase, which catalyzes the irreversible hydrolytic deamination of adenosine and deoxyadenosine to inosine and deoxyinosine respectively, plays an important role in the degradation of adenine nucleotide and purine nucleotide salvage pathway metabolism. We investigated human epidermal adenosine deaminase activity using a radiochemical method,(More)
The actions of peptidase inhibitors derived from Streptomycete on human cathepsin A (hCath A), yeast carboxypeptidase Y (CPY), and wheat carboxypeptidase II (CPW) were analyzed comparatively. Lactacystin and omuralide (clasto-lactacystin beta-lactone), well-known cytoplasmic proteasome inhibitors, both had a potent and non-competitive inhibitory effect on(More)
Benastatin A, isolated from Streptomyces bacteria, is reported to inhibit mammalian glutathione transferases (GSTs). Since GST inhibitors such as ethacrynic acid are suggested to induce apoptosis in some cell lines, the effect of benastatin A on the survival of mouse colon 26 adenocarcinoma cells was compared with that of ethacrynic acid. When cells in(More)