Highly efficient extraction of large molecular-weight keratin from wool in a water/ethanol co-solvent

2019 ◽  
Vol 90 (9-10) ◽  
pp. 1084-1093 ◽  
Author(s):  
Jiahao He ◽  
Duo Xu ◽  
Junyu Li ◽  
Linfeng Li ◽  
Wenbin Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Disulfide Bonds ◽  
Hydrophobic Interactions ◽  
Random Coil ◽  
High Yield ◽  
Mixed System ◽  
Wool Fibers ◽  
Cysteine Hydrochloride ◽  
Α Helix

A large number of wool fiber by-products, short and coarse wool fibers are difficult to spin and are disposed of by the wool industry, creating a burden on the environment. In this study, L-cysteine hydrochloride and sodium sulfite were used as reducing agents to extract keratin from natural wool in an ethanol-water mixed system. The molecular weight of the extracted keratin is up to 130 kDa with a high yield of 67%. It has been proven that the reducing agent destroyed partial disulfide bonds, ethanol destroyed partial hydrogen bonds and hydrophobic interactions, and the α-helix chain was converted into a β-folded chain and random coil after extraction by instrumental analysis using a Fourier transform infrared spectrometer and X-ray diffraction. The recombination of small keratin molecules can be proven by the increase in protein particle size and molecular weight via a particle size analyzer and SDS-PAGE respectively.

Mechanics and hierarchical structure transformation mechanism of wool fibers

2020 ◽  
pp. 004051752094424
Author(s):  
Hongling Liu ◽  
Liang Zhao ◽  
Guosheng Zhang ◽  
Feng Pan ◽  
Weidong Yu
Keyword(s):  
Hierarchical Structure ◽  
Disulfide Bonds ◽  
Solution Concentration ◽  
Single Fiber ◽  
Cold Weather ◽  
Structure Transformation ◽  
Transformation Mechanism ◽  
External Threats ◽  
Wool Fibers ◽  
Α Helix

Various natural protein materials have hierarchical microscale and nanoscale structures that protect animals from suffering cold weather or external threats. Herein, we contribute an effective strategy for exploring the hierarchical structure transformation mechanism by stretching a single fiber and bundle fibers. Taking advantage of controllable stretching, the disulfide bonds and peptide chains were taken apart or reconstructed by the new crosslinking bonds inside the wool fiber. If the temperature, solution concentration and stretching velocity were appropriate, the strain was more than 230% and the microstructure transformation of a single fiber underwent α→ β transition, disulfide bond breakage and macromolecule slippage occurred during the tensile process. The transformation mechanism was modeled and experimentally tested in wool bundle fibers after setting, suggesting that the stretching led to the transformation from α helix to β-pleated sheet, the breakage of disulfide bonds and the slippage of microfibrils. The availability of wool fibers provides many opportunities for bio-friendly cellular substrates and biosensor devices.

Some Physical Parameters of Succinyl-Coenzyme A Synthetase of Escherichia coli

1974 ◽  
Vol 52 (7) ◽  
pp. 594-598 ◽  
Author(s):  
Anita Krebs ◽  
William A. Bridger
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Coenzyme A ◽  
Apparent Molecular Weight ◽  
Random Coil ◽  
Sedimentation Equilibrium ◽  
Physical Parameters ◽  
Equilibrium Studies ◽  
Α Helix ◽  
Succinyl Coenzyme A Synthetase

A physical study of succinyl-coenzyme A synthetase of Escherichia coli has been conducted. The extinction coefficient for the enzyme at 280 nm [Formula: see text] has been evaluated by two independent methods and found to be equal to 4.9 ± 0.2. Sedimentation equilibrium studies show that there is a marked dependence of the apparent molecular weight upon the concentration of the enzyme. At concentrations above 1 mg/ml, the enzyme exists predominantly as an α2β2 tetramer of overall molecular weight near 140 000; at lower concentrations, a significant fraction of the enzyme dissociates to an αβ dimer. The circular dichroism spectrum of the enzyme suggests a high proportion of random coil structure, with small contributions of α-helix and β-structure.

Effects of a Clean Subcritical Degreasing System on Wool Fibers

2021 ◽  
Vol 116 (5) ◽  
Author(s):  
Qiao Xia ◽  
Yinxuan Wang ◽  
Meina Zhang ◽  
Zongcai Zhang ◽  
Hong Dai
Keyword(s):  
Disulfide Bonds ◽  
Structural Changes ◽  
Depth Of Field ◽  
Diffraction Experiment ◽  
X Ray ◽  
Scale Layer ◽  
Wool Fibers ◽  
Α Helix ◽  
Thermal Stability Of ◽  
Scanning Electron

It makes sense to use environmentally friendly methods of degreasing in fur-making process. In this study, subcritical n-pentane was used to degrease wool fibers. Thermogravimetric analysis (TGA) was used to observe and analyze the properties of the subcritical n-pentane degreased wool fibers. The results showed that the thermal stability of the fibers increased. Fourier Transform Infrared (FTIR) spectroscopy was used to analyze the structural changes of macromolecular chains in wool fibers. It was found that when the pressure was higher than 0.4 MPa, the wool fibers underwent a conformational change with the α-helix changing to β-folding. If the pressure was as high as 0.6 MPa, the disulfide bonds in the wool fibers scale layer appeared to break. X-ray powder diffraction experiment was used to study changes in wool fiber aggregation morphology. It was demonstrated that the crystalline zone of wool fibers changed and the fibers index grew, from 22.89% to 30.19%. Field emission scanning electron microscopy and ultra-depth of field microscopy was used to analyze changes in the surface morphology of wool fibers. The results suggested that after the treatment, the wool fibers were not damaged and the impurities on the wool surface were reduced.

scholarly journals Novel Highly Soluble Chimeric Recombinant Spidroins with High Yield

2020 ◽  
Vol 21 (18) ◽  
pp. 6905
Author(s):  
Qiupin Jia ◽  
Rui Wen ◽  
Qing Meng
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Fourier Transform ◽  
Spider Silk ◽  
Aqueous Solubility ◽  
Fiber Formation ◽  
High Yield ◽  
E Coli ◽  
Α Helix ◽  
Β Sheet

Spider silk has been a hotspot in the study of biomaterials for more than two decades due to its outstanding mechanical properties. Given that spiders cannot be farmed, and their low silk productivity, many attempts have been made to produce recombinant spidroins as an alternative. Herein, we present novel chimeric recombinant spidroins composed of 1 to 4 repetitive units of aciniform spidroin (AcSp) flanked by the nonrepetitive N- and C-terminal domains of the minor ampullate spidroin (MiSp), all from Araneus ventricosus. The spidroins were expressed in the form of inclusion body in E. coli with high yield. Remarkably, the aqueous solubility of the four spidroins ranged from 13.4% to over 50% (m/v). The four spidroins could self-assemble into silk-like fibers by hand-drawing. The secondary structures of these proteins, determined by circular dichroism spectrum (CD) and Fourier transform infrared spectrum (FTIR), indicated a prominent transformation from α-helix to β-sheet after fiber formation. The mechanical properties of the hand-drawn fibers showed a positive correlation with the spidroin molecular weight. In summary, this study describes promising biomaterials for further study and wide application.

scholarly journals Effects of High Pressure Modification on Conformation and Digestibility Properties of Oyster Protein

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3273
Author(s):  
Runfang Wang ◽  
Suisui Jiang ◽  
Yujin Li ◽  
Yunsheng Xu ◽  
Tietao Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Protein Solubility ◽  
Random Coil ◽  
Small Particle Size ◽  
Small Peptides ◽  
High Solubility ◽  
Protein Molecules ◽  
Α Helix ◽  
Β Sheet

To expand the utilization of oyster protein (OP), the effects of high pressure (100 to 500 MPa) on chemical forces, structure, microstructure, and digestibility properties were investigated. High pressure (HP) treatment enhanced the electrostatic repulsion (from −13.3Control to −27.8HP200 mV) between protein molecules and avoided or retarded the formation of protein aggregates. In addition, the HP treated samples showed uniform distribution and small particle size. The changes in electrostatic interaction and particle size contributed to the improvement of solubility (from 10.53%Control to 19.92%HP500 at pH 7). The stretching and unfolding of protein were modified by HP treatment, and some internal hydrophobic groups and -SH groups were exposed. HP treatment modified the secondary structure of OP. The treated samples contained less α-helix and β-sheet structures, whereas the proportions of β-sheet and random coil structures were increased. The treated samples have high digestibility in the stomach (from 26.3%Control to 39.5%HP500) and in the total digestive process (from 62.1%Control to 83.7%HP500). In addition, the total digestive production showed higher percentages of small peptides (<1 kDa) after HP treatment. The protein solubility and digestibility were increased after HP treatment, and high solubility and high digestibility might increase the chance that OP become a kind of protein supplement.

scholarly journals Effects of High-Intensity Ultrasound Pretreatment on Structure, Properties, and Enzymolysis of Walnut Protein Isolate

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 208
Author(s):  
Fei Zhao ◽  
Xiaosong Zhai ◽  
Xuemei Liu ◽  
Meng Lian ◽  
Guoting Liang ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
High Intensity ◽  
Tertiary Structure ◽  
Fluorescence Emission ◽  
Protein Isolate ◽  
Random Coil ◽  
Degree Of Hydrolysis ◽  
Ζ Potential ◽  
Α Helix

The purpose of this paper was to investigate the effect of high-intensity ultrasonication (HIU) pretreatment before enzymolysis on structural conformations of walnut protein isolate (WPI) and antioxidant activity of its hydrolysates. Aqueous WPI suspensions were subjected to ultrasonic processing at different power levels (600–2000 W) and times (5–30 min), and then changes in the particle size, zeta (ζ) potential, and structure of WPI were investigated, and antioxidant activity of its hydrolysates was determined. The particle size of the particles of aqueous WPI suspensions was decreased after ultrasound, indicating that sonication destroyed protein aggregates. The ζ-potential values of a protein solution significantly changed after sonication, demonstrating that the original dense structure of the protein was destroyed. Fourier transform infrared spectroscopy indicated a change in the secondary structure of WPI after sonication, with a decrease in β-turn and an increase in α-helix, β-sheet, and random coil content. Two absorption peaks of WPI were generated, and the fluorescence emission intensity of the proteins decreased after ultrasonic treatment, indicating that the changes in protein tertiary structure occurred. Moreover, the degree of hydrolysis and the antioxidant activity of the WPI hydrolysates increased after sonication. These results suggest that HIU pretreatment is a potential tool for improving the functional properties of walnut proteins.

scholarly journals Monitoring the Effects of Hemicellulase on the Different Proofing Stages of Wheat Aleurone-Rich Bread Dough and Bread Quality

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2427
Author(s):  
Boyu Tian ◽  
Chenxia Zhou ◽  
Dongxiao Li ◽  
Jiawei Pei ◽  
Ailiang Guo ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Disulfide Bonds ◽  
Hydrophobic Interactions ◽  
Hydrolytic Activity ◽  
Intermolecular Forces ◽  
Bread Quality ◽  
Ionic Bonds ◽  
Α Helix ◽  
Β Sheet

This study investigated the effects of a hemicellulase dosage (20, 40, and 60 mg kg−1 of flour) on the bread quality and rheological properties of wheat aleurone-rich flour. The results showed that hemicellulase could soften dough and improve extensibility. At the optimum hemicellulase dosage (40 mg kg−1 of flour), the bread specific volume increased by 40.91% and firmness of breadcrumb decreased by 104.57% compared to those of the control. Intermolecular forces indicated that the gluten network during the proofing was mainly strengthened via disulfide bonds, hydrophobic interactions, and hydrogen bonds but not through ionic bonds after hemicellulase addition. Fourier infrared spectroscopy indicated that the hydrolytic activity of hemicellulase catalyzed the transition from α-helix to β-sheet, which verified that viscoelasticity of gluten was enhanced at a dosage of 40 mg kg−1 of flour. These results suggested that hydrolyzation of hemicellulase contributed to the structural of gluten changes, thereby improving the quality of wheat aleurone-rich bread.

scholarly journals Dispersion polymerization of n-butylacrylate under the action of acrylic acid and N-isopropylacrylamide copolymers

2019 ◽  
pp. 34-38 ◽  
Author(s):  
N. S. Serkhacheva ◽  
E. V. Chernikova ◽  
N. I. Prokopov ◽  
M. S. Balashov ◽  
V. V. Ogay ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Acrylic Acid ◽  
Particle Size Distribution ◽  
Dispersion Polymerization ◽  
High Yield ◽  
Alcohol Medium ◽  
Water Alcohol

The regularities of dispersion radical polymerization of n-butylacrylate in water-alcohol medium under the action of polymer tritiocarbonates based on copolymers of acrylic acid and N-isopropylacrylamide have been investigated. The conditions for the formation of a block copolymer with controlled molecular weight and high yield have been found. The conditions of formation of stable suspensions of block copolymers with unimodal particle size distribution have been determined.

Characterization of Putative a (1,3)-β-D-glucan (curdlan) Synthase for a Low Molecular Weight Curdlan Biosynthesis from Agrobacterium sp. M503

2013 ◽  
Vol 807-809 ◽  
pp. 2031-2034
Author(s):  
Yu Mei Li ◽  
Qiang Li ◽  
Sheng Han ◽  
Dong Xue Song ◽  
Yan Hong Qu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Random Coil ◽  
Low Molecular Weight ◽  
Base Pairs ◽  
Reading Frame ◽  
Coil Structure ◽  
Α Helix ◽  
Encoding Protein ◽  
Β Sheet

A β-(1,3)-D-glucan (curdlan) synthase gene for a low molecular weight curdlan biosynthesis, crdSAg, from Agrobacterium sp. M503 was cloned and its encoding protein was characterized by several online protein analysis softwares. The crdSAg consists of 1965-base-pairs Open Reading Frame (ORF) encoding a protein with molecular weight approximate 73.5 kDa, which contains the conserved domain of CESA-CelA_like belonging to glycosyltransferase family 2 (GT2). Moreover, CrdSAg was a membrane protein with seven hydrophobic transmembrance domains. The second structure analysis indicated it was composed of 43.12% α-helix, 17.89% β-sheet, and 38.99% random coil structure. These data will lay a foundation to clarify the biosynthesis mechanism of the low molecular weight curdlan.

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