Variety of Effect of n-Alcohols on Microenvironment of Some Proteases in Peptide Synthesis or Z (N-Benzyloxycarbonyl) : Amino Acid Ester Hydrolysis

To investigate the interaction of proteases (thermolysin, α-chymotrypsin, papain and pepsin) with organic solvent molecules, buffer systems in which n-alcohols were dissolved as to make a one-phase medium were used in the case of peptide synthesis or Z-amino acid hydrolysis as model reactions. The chain length of n-alcohols gave different characteristics of the effective patterns to the enzymes, and also each protease was affected in different modes of effective profiles by n-alcohols. Activity of α-chymotrypsin was increased by n-alcohols higher than n-hexanol grdually with increase of their concentration just over the saturation to the buffer. The activation was proposed to be non-essential by kinetics. Meanwhile, n-pentanol to α-chymotrypsin showed to be an uncompetitive inhibitor.Article信州大学農学部紀要. 32(1-2): 15-22 (1995)journal articl

Synthesis of N-Substituted Glucosamine Derivatives and Their Angiotensin I Converting Enzyme Inhibitory Activity

Inhibitory activity of glucosamine derivatives against angiotensin I converting enzyme (ACE) was investigated. Many N-substituted glucosamine derivatives were synthesized via 1,3,4,6-tetra-O-acetyl-glucosamine hydrochloride. Among them, N-(phenylalanyl-alanyl-prolyl)-glucosamine was found to be the most effective for ACE inhibition, and the half inhibitory concentrations (IC50_) was estimated as 300μM. Furthermore, N-(3,7-dimethyl-2(E/Z), 6-hexadien-carbonyl)-glucosamine and N-(p-dimethylamino benzoyl)-glucosamine were found to be effective for the inhibition of ACE, and their IC50 values were estimated as 5 mM and 8 mM, respectively.Article信州大学農学部紀要. 31(1): 45-54 (1994)departmental bulletin pape

Synthesis of Aldoxime Derivatives and Taste Evaluation, Part II

The sweet taste evaluation of peptide aldoximes was investigated. Many derivatives were synthesized by introducing aldoxime group into the carboxyl terminal of amino acids or peptides. N-substituted hydrophobic amino acid or N-substituted aminoacyl-glycine were used as the materials to replace the terpenoid backbone of perillartine. On sensory evaluation, some of these derivatives exhibited sweetness. The maximum sweetness was found in compounds with Z-aminoacyl aldoximes. Sweetness is subjective and dependent upon a number of factors such as steric hindrance of N-protecting groups, solubility in water, concentration of sweetener and other interfering ingredients in the product.Article信州大学農学部紀要. 30(1): 33-40 (1993)journal articl

Thermolysin Activation by Water-miscible Organic Solvents in Aqueous-organic One-phase Reaction System is not Dominated by Their Physical or Physicochemical Parameters

Thirteen water-miscible organic solvents, except for alcohols, with infinite solubility in water; and two physical and eighteen physicochemical parameters were adopted for enzymatic peptide synthesis in water-organic one-phase reaction system. Results showed that the activation of thermolysin by water-miscible organic solvents has striking similarity with that of water-immiscible solvents. They exhibited common activation profile and kinetic mechanism. It was demonstrated that activation is not controlled by any of the solvent parameters-suggesting the involvement of specific atoms and/or groups.Article信州大学農学部紀要. 35(1):51-57(1998)journal articl

Effect of Ketonic Organic Solvents on Thermolysin: A Spectrophotometric Approach

Ultraviolet spectra of thermolysin on mixing with n-alkyl ketones were investigated. Hypochromic effect of UV spectra of enzyme and model compounds was observed. A clear batho-chromic shift (red shift) of thermolysin spectrum was also demonstrated. With increase in chain length of ketones, the red shift was found reduced. The hypochromic and bathochromic effects were significantly suppressed when enzyme or model compounds were pre-treated with inhibitor (phosphor-amidon). There had been no such effect of ketones upon mixing with substrates. It was speculated that ketones interact with the UV sensitive aromatic amino acid residues at the microenvironment of active site of enzyme.Article信州大学農学部紀要. 34(1): 31-37 (1997)journal articl