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Kentaro Shiraki
University of Tsukuba
221Publications
27H-index
2,913Citations
Publications 221
Newest
#1T. MoriH-Index: 18
Last.Yohei YamamotoH-Index: 21
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Disordered systems exhibit universal excitation, referred to as the boson peak, in the terahertz region. Meanwhile, the so-called fracton is expected to appear in the nanoscale region owing to the self-similar structure of monomers in polymeric glasses. We demonstrate that such excitations can be detected using terahertz spectroscopy. For the interaction between terahertz light and the vibrational density of states of the fractal structure, we formulate an infrared light-vibration coupling coeff...
Therapeutic antibodies for subcutaneous (SC) injection must be formulated at high concentrations because of the large therapeutic dose and volume restriction. However, concentrated antibody solutions have undesirably high viscosity, which hampers SC injection. In this study, we demonstrated that hydantoin and its derivatives suppressed the viscosity of concentrated antibody and bovine serum albumin solutions. Hydantoin derivatives, in particular 1-methylhydantoin, appeared more effective. Both h...
Abstract Aggregation of immunoglobulin G (IgG) is a serious concern that results in immunogenicity in pharmaceutical applications. Removal of the small and soluble aggregates in protein solutions through a simple method remains challenging. Here we show that an aqueous two-phase system (ATPS) can be used for the elimination of soluble aggregates from IgG solution. Polyethylene glycol (PEG) and dextran (DEX) were selected as components of the ATPS. As expected, IgG monomers were partitioned into ...
#1Chika Shibata (University of Tsukuba)H-Index: 1
#2Kazuki Iwashita (University of Tsukuba)H-Index: 4
Last.Kentaro Shiraki (University of Tsukuba)H-Index: 27
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Abstract Aqueous two-phase system (ATPS) containing salts has been used for protein purification and enrichment. However, it is unclear how proteins are partitioned in the top or bottom phases of the system. In this study, we demonstrate that the partition of proteins in salt-containing ATPS (SATPS) depends only on the relation between the protein-surface amino acids and the type of salt using SATPS. The partition coefficients of four proteins changed depending on the kind of salt, according to ...
#1Atsushi Hirano (AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 15
#2Kazuki Iwashita (University of Tsukuba)H-Index: 4
Last.Tomoshi Kameda (AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 13
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Abstract Salt solutions are widely used as eluents for ion-exchange chromatography. In general, salts reduce the retention of applied solutes on ion-exchange columns via electrostatic screening effects. The reverse phenomenon, namely, salt-enhanced retention, has not been reported. Here, we report that cations, including arginine, guanidine and sodium ions, enhance the retention of uncharged aromatic solutes on a cation-exchange resin, i.e., a negatively charged resin, with carboxyl groups, wher...
#1Kazuki Iwashita (University of Tsukuba)H-Index: 4
#2Akihiro HandaH-Index: 4
Last.Kentaro Shiraki (University of Tsukuba)H-Index: 27
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Abstract Ovotransferrin (OVT) is the main protein component of egg white responsible for initial gelation due to its high thermal susceptibility. Co-aggregation of lysozyme (LYZ) is involved in OVT aggregate formation at low temperatures during pasteurization. Undesirable formation of aggregates limits the degree of thermal processing that can be applied to egg white products. However, the characteristics of co-aggregates of OVT and LYZ have not been elucidated. Here, we determined the thermal c...
#1Takahiro Nonaka (University of Tsukuba)H-Index: 1
#2Noriko Tsurui (Ajinomoto)H-Index: 1
Last.Kentaro Shiraki (University of Tsukuba)H-Index: 27
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Abstract Cell surface protein B (CspB) from Corynebacterium glutamicum is used as a pH-responsive peptide tag to enable a simple solid–liquid separation method for isolating a CspB fusion protein. Here we demonstrate the first application of a CspB tag for the purification of Teriparatide, which is a biologic drug that is prescribed for osteoporosis. The Teriparatide was constructed as CspB50TEV-Teriparatide, comprising 50 amino acid residues of CspB, the cleavage site of TEV protease, and Terip...
#1Masahiro Mimura (University of Tsukuba)H-Index: 1
#2Keisuke Tsumura (University of Tsukuba)
Last.Kentaro Shiraki (University of Tsukuba)H-Index: 27
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Liquid droplets of protein–polyelectrolyte complexes (PPCs) have been developed as a new candidate for stabilization and concentration of protein drugs. However, it remains unclear whether additives affect the precipitation and redissolution yields of PPCs. In the present study, we investigated the PPC formation of human immunoglobulin G (IgG) and poly-L-glutamic acid (polyE) in the presence of various additives that have diverse effects, such as protein stabilization. Alcohols, including ethano...
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