Studies on applications of lypolytic enzymes in detergency II. Evaluation of adaptability of various kinds of lipases in practical laundry conditions

Journal of the American Oil Chemists' Society - Kinetic parameter of hydrolysis, degree of hydrolysis, pH and temperature characteristics and positional specificity of hydrolysis of seven kinds...     

Environmental effect on room- temperature ductility of isothermally forged tial- base alloys

Isothermally forged TiAl-base alloys (Al-rich, Mn-containing, and Cr-containing TiAl) were heat-treated in various conditions, and equiaxed grain structures consisting of γ and α₂ or Β phases were obtained. The heat-treated alloys were tensile tested in vacuum and air at room temperature, and the environmental effect on tensile elongation was studied. The ductility of the alloys consisting of equiaxed γ grains and a large amount of α₂ grains was not largely affected by laboratory air, and a decrease in the amount of α₂ grains resulted in a large reduction of ductility in air. The Β phase in the Cr-containing alloy improved the ductility in vacuum, but it resulted in a large reduction of ductility in air. Formerly with Kougakuin University, Shinjyuku-ku, Tokyo, Formerly with National Research Institute for Metals, Meguro-ku, Tokyo,     

Synthesis and surface properties of novel fluoroalkyl end-capped amphiphilic fullerene cooligomers

New fluoroalkyl end-capped fullerene cooligomers were prepared by the reactions of fluoroalkanoyl peroxides with fullerene and comonomers such as acryloylmorpholine, N,N-dimethylacrylamide and acrylic acid. These fluorinated fullerene cooligomers were easily soluble in water and common organic solvents, and were able to reduce the surface tensions of both water and benzene, quite effectively. Additionally, these fullerene cooligomers were found to form a stable monomolecular film at the air-water interface, and the modified polystyrene surface treated with these cooligomers was shown to have a strong hydrophilicity with good oil repellency.     

Deletion and insertion of a 192-residue peptide in the active-site domain of glycosyl hydrolase family-2 beta-galactosidases

The monomeric multimetal-binding beta-galactosidase of Saccharopolyspora rectivirgula (srbg), a glycosyl hydrolase family-2 enzyme, has a unique sequence consisting of 192 amino acid residues with no similarity to known proteins. This 192-residue sequence (termed the "iota [iota] sequence") appears to be inserted into a sequence homologous to the active-site domain of the Escherichia coli lacZ enzyme (lacZbg). To assess the effects of the t sequence at specific sites of beta-galactosidase on the catalytic functioning and molecular properties of beta-galactosidase, deletion or insertion mutants of beta-galactosidases were constructed, expressed in LacZ- E. coli strains, and characterized: srbgdelta in which the iota sequence was deleted from srbg, and lacZbgI, in which the 192-residue iota sequence was inserted into the corresponding position (between Asp591 and Phe592) in the active-site domain of lacZbg. srbgdelta was a catalytically inactive, dimeric protein which retained multimetal-binding characteristics, suggesting that the iota sequence is very important for maintaining the structure necessary for the catalytic functioning and the monomeric structure of srbg but is not responsible for the unique metal ion requirements of srbg. On the other hand, lacZbgI existed as a mixture of a monomer, a tetramer, and higher multimers. The monomeric species was inactive, whereas the tetramer and other multimers were catalytically active (V(max )K(m) value, 25% of that of lacZbg) and highly specific for beta-D-galactoside. The tetrameric lacZbgI was activated by Mg2+ and Mn2+ with lowered metal affinities, and the stoichiometry of metal binding was unchanged from that of lacZbg. These results, along with the published stereo structure of lacZbg, suggest that, in lacZbgI, the inserted 192-residue iota peptide could fold independently of the lacZbg domains into a "sub-domain," lying distant from the active site and subunit interfaces.     

Novel sugar phosphotransferase system applicable to the efficient labeling of the compounds synthesized via the non-mevalonate pathway in Escherichia coli

It is known that 1-deoxy-D-xylulose taken up by Escherichia coli is used as the precursor of the compounds synthesized via the non-mevalonate pathway, such as isoprenoids, probably after conversion into 1-deoxy-D-xylulose 5-phosphate. In this report, we show that a novel phospho(enol) pyruvate-dependent phosphotransferase system catalyzes the uptake and phosphorylation of 1-deoxy-D-xylulose.     

Orbit systematics in anisotropic Kepler problem

We revisit the Anisotropic Kepler Problem (AKP), which concerns with trajectories of an electron with anisotropic mass term in a Coulomb field. This is one of the most fundamental fields in Quantum Chaos. Nowadays various quantum systems are challenging us. Classical theories of these may have chaos. Quantum mechanics have developed from integrable cases and may have to be reformulated for such cases. AKP then serves as a suitable testing ground for quantum chaos. We first review a pioneering work by Martin Gutzwiller (J Math Phys (1977) 18:106). We shall show the systematics of the trajectories using ample figures from an extensive numerical analysis. Then we focus on the rolê of hyperbolic singularities and we comment on the approximations in an analytic formulation. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Synthesis of Succinic Gemini Surfactants and the Effect of Stereochemistry on Their Monolayer Behaviors

In this work, succinic gemini surfactants, dl‐ and meso‐2,3‐bis(alkyl)succinic acids (alkyl: C₆H₁₃–C₁₃H₂₇), were successfully synthesized by oxidative coupling of enolates of fatty acid tert‐butyl esters with copper(II) bromide followed by treatment with CF₃COOH. Focusing on the influence of stereochemistry (dl‐ and meso‐) of succinic geminis, their monolayer behaviors at the air–water interface were explored using surface pressure–area (Π–A) isotherms, the compression modulus of monolayers (ε_s), and Brewster angle microscope (BAM) analysis. meso‐2,3‐Bis(undecyl)succinic acid showed a unique isotherm where the surface pressure drastically decreased at A = ~0.56 nm² (Π = 21.9 mN m^?1) regardless of compression rates and subphase temperatures, while dl‐isomer showed the common isotherm of gas → liquid‐expanded → liquid‐condensed phase transitions. BAM analysis on meso‐2,3‐bis(undecyl)succinic acid films at the air–water interface showed that small islands of aggregates appear just after the maximum pressure (A = ~0.56 nm²), and on further compression needle‐shaped assemblies appear that can grow in size. It was reasonably concluded that hydrophobic interactions can operate more effectively in meso‐isomers than in dl‐isomers, and that meso‐molecules can “jump up” to cause a transition from monolayer to bilayer. This is the first finding of the “jumping‐up” phenomenon of gemini surfactants having meso‐stereochemistry.     

A novel synthesis of succinic acid type Gemini surfactant by the functional group interconversion of Corynomicolic acid

2,3-Bis(undecyl)succinic acid, succinic acid type Gemini surfactant, was successfully synthesized from Corynomicolic acid by the functional interconversion of OH of Corynomicolic acid to COOH via (1) mesylation of OH of syn-isomer, (2) elimination of methanesulfonate group using base to E-alpha,beta-unsaturated ester, (3) Michael addition of CN(-) with 18-crown-6 and (4) hydrolysis. In most hydrolysis conditions, a mixture of syn- and anti-2,3-bis(undecyl)succinic acid was obtained, but hydrolysis in 75% H(2)SO(4) gave only anti-2,3-bis(undecyl)succinic anhydride. After converting a mixture of syn- and anti-2,3-bis(undecyl)succinic acids to corresponding acid anhydrides, syn- and anti-anhydride isomers were separated by column chromatography, and by following hydrolysis syn- and anti-2,3-bis(undecyl)succinic acid was selectively prepared. Based on the surface tension measurement, the effect of stereochemistry on surface tension isotherms was discussed in terms of the hydrophobic interaction between two alkyl groups and the electrostatic repulsion between two hydrophilic COO(-) groups.     

Effect of mutagenesis at the region upstream from the G(Q/E) motif of three types of geranylgeranyl diphosphate synthase on product chain-length

(All-E) geranylgeranyl diphosphate synthases have been classified into three types based on the characteristic sequences around the first aspartate rich motif, which is highly conserved among the enzymes. In type I geranylgeranyl diphosphate synthases, which consist of archaeal enzymes, a bulky amino acid residue at the 5th position upstream from the motif plays a main role in the product determination, by blocking further elongation of prenyl chain as the bottom of the reaction cavity. On the other hand, type III geranylgeranyl diphosphate synthases, which consist of the enzymes from eukaryotes except for plants, use a bulky amino acid residue at the 2nd position upstream from the conserved G(Q/E) motif for product chain-length determination. Thus we introduced mutations into the region upstream from the G(Q/E) motif of geranylgeranyl diphosphate synthases of the three different types to confirm the importance of the region for the product chain-length determination. The results of the mutational analyses indicated that not only the 2nd but also the 3rd position upstream from the G(Q/E) motif is involved in the product chain-length determination mechanism in types I and III geranylgeranyl diphosphate synthases, while the amino acid substitution in this region did not affect the chain-length of the products of type II geranylgeranyl diphosphate synthase, which consist of the enzymes from bacteria and plants. The region upstream from the G(Q/E) motif possibly contributes to the product determination in the wide range of geranylgeranyl diphosphate synthases, as well as that around the first aspartate rich motif.     

Effects of hydrophobic chain length on temperature dependence of monolayer behavior of ester-type tartaric geminis

Ester-type tartaric gemini amphiphiles bearing two carboxyl groups and two hydrophobic alkanoyl groups were prepared from L-tartaric acid, and the pressure-area (π-A) isotherms for a series of symmetric tartaric gemini amphiphiles were measured by the conventional film-balance technique. The effects of the length of the hydrophobic alkanoyl chains and of the subphase temperature (T(sub)) on the π-A isotherms for these compounds were examined. As the length of the hydrophobic alkyl chain increased, a more tightly packed monolayer was formed at the air-water interface. The melting temperature (T(m)) of the monolayer on the water surface was evaluated from the subphase temperature (T(sub)) dependence of the monolayer static elasticity ε(s), based on a π-A isotherm. A clear relationship between T(m) and hydrophobic carbon number (n) was observed for 2D monolayers of tartaric geminis on water surfaces, as well as for fatty acids and/or 3D solids.