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Glycoprotein showing inhibitory activity against mast cell degranulation and hyaluronidase activity was purified from the hot water extract of mint plant (Perilla frutescens Britton). The purified inhibitor gave a single band detected with Coomassie brilliant blue staining and periodic acid-Schiff staining on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The molecular mass was estimated to be 6.0 kDa on SDS-PAGE. The inhibitor did not become inactivated when boiled for 30 min or digested with trypsin, V8 protease, or proteinase K but was inactivated by NaIO(4) oxidation. The inhibitor prevented mast cell degranulation and hyaluronidase activity (IC(50) = 0.42 mg/mL) in a dose-dependent manner. The inhibitor also inhibited the protein kinase C activity. It is possible to purify and characterize a glycoprotein with putative pharmacological properties from mint plants.

D-Aminoacylase for enzymatic resolution of DL-amino acids was produced in the presence of inducer by Streptomyces olivaceus and almost all the activity was found in cell fraction. The partial purification and properties of this induced enzyme were studied. The enzyme had a molecular weight of about 45,000 and was specific for the hydrolysis of N-acetyl D amino acids. The optimum pH was found to be at pH 7.0 and the activity was remarkably inhibited by the presence of Hg2+ or Ag2+. Enzyme stability was increased by the addition of Cot+. Michaelis constants (Km) for several preferred substrates were between 1.13 x 10-s and 2.95 x 10-3 M.

D-Aminoacylase was found to be produced not only by S. olivaceus 62 3 isolated from soil but also by three strains of type culture of Streptomyces species. All four of these strains produced D aminoacylase intracellularly only when an inducer was added to the culture medium. D-Amino acids or N-acetyl-D-amino acids were effective as inducers. As S. tuirus showed the highest D-aminoacylase activity, the enzyme extract of this strain was subjected to further investigation to determine the optimal conditions for optical resolution of N-acetyl-DL-phenylglycine. Almost all contaminating L-aminoacylase in the enzyme extract could be eliminated by DEAE-Sephadex adsorption. D-Phenylglycine of 99.9% optical purity was obtained after complete hydrolysis of D-isomer with the use of D-aminoacylase solution.

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