Probability Density Functional Method of Enzyme Effect on Denatured Protein Soil.

Protein soils must be removed for both appearance and hygienic reasons. They are denatured by heat treatment or bleaching and cleaned using enzymes. Among the various types of protein soils, blood soils are the most noticeable and known to be denatured by heat and bleaching by oxidation. We verified herein that the detergency of heat and oxidatively denatured hemoglobin is greatly improved by the enzyme immersing treatment in the detergency with SDS and can be analyzed using the probability density functional method. The probability density functional method evaluates the cleaning power by assuming that the adhesion and cleaning force of soils are not uniquely determined, but instead have a distribution in intensity, with a usefulness that had recently been demonstrated. This analytical method showed that the cleaning power of the enzyme immersing treatment improved when the soil adhesive force was decreased due to denatured protein degradation, even though the cleaning power of the SDS remained unchanged, and the values were consistent with those in the cleaning test. In conclusion, the probability density functional method can be used to analyze enzymatic degradation of denatured protein soils and the resulting changes in their detergency.

Application of Colloidal Dispersions of Bioshell Calcium Oxide (BiSCaO) for Disinfection.

Bioshell calcium oxide (BiSCaO) is a scallop-shell powder heated at a high temperature. BiSCaO is composed mainly of calcium oxide and exhibits broad microbicidal properties. The aim of this study is to evaluate the disinfection and decontamination abilities of BiSCaO colloidal dispersions with that of commercially available bioshell calcium hydroxide (BiSCa(OH)2) following the formation of flocculants/precipitates under strongly alkaline conditions (pH 11.5-12.2). Various concentrations of BiSCaO and BiSCa(OH)2 colloidal dispersions were prepared by mixing with Na-polyPO4 (PP) and Na-triPO4 (TP) as flocculating agents. The microbicidal activities, and the degree of flocculation/precipitation of trypan blue, albumin, chondroitin sulfate, heparin, non-anticoagulant heparin carrying polystyrene (NAC-HCPS), and low-molecular-weight heparin/protamine nanoparticles (LMWH/P NPs) were dependent on the pH, the average particle diameter, and the concentration of BiSCaO or BiSCa(OH)2 and of the phosphate compound. BiSCaO (average particle diameter: 6 µm) colloidal dispersions (0.2 wt.%) containing 0.15 wt.% PP or TP exhibited substantially stronger microbicidal activity and flocculation/precipitation under strongly alkaline conditions. These results suggest that BiSCaO colloidal dispersions together with phosphate compounds have practical applicability for disinfection.

Inhibitory effect of gnetin C, a resveratrol dimer from melinjo (Gnetum gnemon), on tyrosinase activity and melanin biosynthesis.

Tyrosinase is the key enzyme involved in melanogenesis. The aim of this study was to investigate the in vitro inhibitory effects of gnetin C, a resveratrol dimer isolated from melinjo (Gnetum gnemon) seeds, on tyrosinase activity and melanin biosynthesis in murine B16 cells. The inhibitory activities of gnetin C and resveratrol were shown to be almost equal against tyrosinase and melanin biosynthesis in the cells. The IC(50) values of gnetin C activity against tyrosinase and melanin biosynthesis were 7.0 and 7.6 µM, respectively, whereas resveratrol demonstrated IC(50) values of 7.2 and 7.3 µM, respectively. These results indicated that gnetin C inhibited melanogenesis, in a manner similar to that of resveratrol, by inhibiting tyrosinase and may therefore function as a new skin-whitening agent. However, the direct effects of gnetin C and resveratrol on murine tyrosinase activities were not equal. The IC(50) value of resveratrol was 10.1 µM, while gnetin C only exhibited a 25.2% enzyme inhibition at 16 µM. The IC(25) values for gnetin C and resveratrol were 15.5 and 4.0 µM, respectively. Therefore, it is suggested that the effects of gnetin C may be due to mechanisms other than the direct inhibition of tyrosinase activity.

Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch.

Molluscan smooth muscle can maintain tension over extended periods with little energy expenditure, a process termed catch. Catch is thought to be regulated by phosphorylation of a thick filament protein, twitchin, and involves two phosphorylation sites, D1 and D2, close to the N and C termini, respectively. This study was initiated to investigate the role of the D2 site and its phosphorylation in the catch mechanism. A peptide was constructed containing the D2 site and flanking immunoglobulin (Ig) motifs. It was shown that the dephosphorylated peptide, but not the phosphorylated form, bound to both actin and myosin. The binding site on actin was within the sequence L10 to P29. This region also binds to loop 2 of the myosin head. The dephosphorylated peptide linked myosin and F-actin and formed a trimeric complex. Electron microscopy revealed that twitchin is distributed on the surface of the thick filament with an axial periodicity of 36.25 nm and it is suggested that the D2 site aligns with the myosin heads. It is proposed that the complex formed with the dephosphorylated D2 site of twitchin, F-actin and myosin represents a component of the mechanical linkage in catch.