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C-reactive protein (CRP) and serum amyloid P component (SAP), two major classical pentraxins in humans, are soluble pattern recognition molecules that regulate the innate immune system. They have a...

Mass transport of divalent amino acids, arginine and histidine, was investigated in an ion exchange system using DIAION SK104, SK1BL, and SK112. Ion exchange equilibrium constants of arginine were 5.0 g/cm3 for SK104 (4 wt% D.V.B.), 25.0 g/cm3 for SK1BL (8 wt% D.V.B.) and 25.0 g/cm3 for SK112 (12 wt% D.V.B.). The ion exchange equilibrium constant of histidine was 8.0 g/cm3 for SK1BL (8 wt% D.V.B.). Resin phase diffusivities of divalent amino acids are measured by batch uptake experiments. Resin phase diffusivities of divalent arginine were decreased from 9.0 × 10−8 cm2/s to 1.6 × 10−8 cm2/s while the D.V.B. content in resin increases from 4 wt% to 12 wt%. Resin phase diffusivity of histidine for 8 wt% D.V.B. resin was 7.0 × 10−8 cm2/s. The steric hindrance model was able to describe measured resin phase diffusivities.

The blocking of step motion on (100) and (001) faces of an L-isoleucine (L-Ile) crystal caused by the addition of an aqueous solution of L-norleucine (L-Nle) to the L-Ile solution was investigated using an atomic force microscope (AFM). The step motion was blocked in the presence of L-Nle. Crystal growth of L-Ile was inhibited along the a-, b-, and c-axes in the presence of L-Nle. Also, the blocking of step motion on the L-Ile (001) face of an L-Ile seed crystal was observed.

Toshimichi Kamei On BCAA (Branched Chain Amino Acids) crystallization process, impurity amino acids (guest amino acids) are easily incorporated to the host amino acid(a purified amino acid). Because host and guest amino acids have similar molecular structures and physical-chemical properties, therefore, in many cases, it is difficult to separate a host amino acid and a guest amino acid each other in the simple crystallization method (such as cooling or concentration crystallization conducted in water solvent). In above cases, HCl or precipitant is added to the mixed solution of a host and guest amino acid in order to separate them by generating the salt of a host amino acid. (A host amino acid crystallizes as a hydrochloride or precipitant salt.) But this process is complicated because de-hydrochloric acid or deprecipitant process is needed after crystallization to make the products. Therefore, it is thought that development of the simple crystallization method is necessary in order to make a process simpler. In order to develop the simple crystallization method, it is necessary to elucidate the incorporation mechanism of these amino acids at first, and then decide the crystallization condition based on this mechanism. We explored the mutual incorporation tendency of Branched Chain Amino Acids (L-leucine, Lisoleucine, L-valine ) and isomorphic amino acids in cooling crystallization conducted in water solvent. As a result, in most cases, a guest amino acid whose side chain is longer than that of a host amino acid was incorporated easily in a host amino acid. In this case, a solid solution was formed, and the c-axis of a host crystal structure was extended. Also the crystal growth was inhibited. Using these results, a mechanism for mutual incorporation of these amino acids was proposed.

In beta2-microglobulin-related (A beta2M) amyloidosis, a serious complication in patients on long-term dialysis, partial unfolding of beta2-microglobulin (beta2-m) is believed to be prerequisite to its assembly into A beta2M amyloid fibrils. Many kinds of amyloid-associated molecules, (e.g., apolipoprotein E (apoE), glycosaminoglycans (GAGs), proteoglycans (PGs)) may contribute to the development of A beta2M amyloidosis. In 1990s, the formation of A beta2M amyloid fibrils in vitro was first observed at low pH (2.0-3.0). Very recently, low concentrations of 2,2,2-trifluoroethanol (TFE) and the sub-micellar concentration of sodium dodecyl sulfate, a model for anionic phospholipids, have been reported to cause the extension of A beta2M amyloid fibrils at a neutral pH, inducing partial unfolding of beta2-m and stabilization of the fibrils. Moreover, apoE, GAGs, and PGs were found to stabilize A beta2M amyloid fibrils at a neutral pH, forming a stable complex with the fibrils. Some GAGs, especially heparin, enhanced the fibril extension in the presence of TFE at a neutral pH. Some PGs, especially biglycan also induced the polymerization of acid-denatured beta2-m. These findings are consistent with the hypothesis that in vivo, specific molecules that affect the conformation and stability of beta2-m and amyloid fibrils will have significant effects on the deposition of A beta2M amyloid fibrils.

In mice, apolipoprotein A-II (apoA-II) is the most important protein associated with senile amyloidosis. We evaluated the ability of synthetic apoA-II partial peptides to polymerize into ...

In order to elucidate the pathogenesis of A beta2M amyloidosis, we established an experimental system to study the mechanism of amyloid fibril formation or degradation in vitro. We compared the kinetics of A beta2M amyloid fibril (fA beta2M) extension with native beta2microglobulin (n-beta2M) purified from the urine of a patient suffering from renal insufficiency, with that with recombinant beta2M (r-beta2M) in vitro. n-Beta2M and r-beta2M were incubated with fA beta2M purified from synovial tissues excised from A beta2M amyloidosis patients. The fA beta2M extension reaction could be explained by a first-order kinetic model in both beta2Ms. The extension reaction was greatly dependent on the pH of the reaction mixture and maximum around pH 2.5-3.0 in both beta2Ms. The fA beta2M extended with both beta2Ms assumed the similar helical filament structure, although the fibrils extended with r-beta2M were slightly wider than those extended with n-beta2M and the former fibrils assumed a helical structure more clearly as compared to the latter. In order to obtain pure, unmodified fA beta2M, we next extended fA beta2M repeatedly by the algorithmic protocol with r-beta2M. As the generation of the extended fibrils proceeded, the initial rate of the extension reaction increased The ultrastructure of fibrils was completely preserved throughout the repeated extension steps. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting revealed that fA beta2M extended repeatedly with r-beta2M were composed solely of r-beta2M. The use of these r-beta2M and fA beta2M will be advantageous to assess the effects of several amyloid-associated molecules in the formation or degradation of fA beta2M in vitro.

A study is presented for the separative performance of a centrifuge for SF6 isotope separation. Full solutions are obtained with use of the existing computer code for the equations governing compressible fluid flow in strong rotation and corresponding to diffusion phenomenon. A standard case is fixed with some considerations, and the calculation result gives 37% separation efficiency. Parameter surveys are performed with changing feed flow rate, temperature difference between top and bottom end plates, static pressure at product scoop inlet, thickness of scoop and radius of inner opening of waste baffle plate. These results and some considerations are shown, where the obtained maximum value of the separation efficiency is 42%.