Formation of the poly(L-lysine) complex with pectin of various esterification degree

1985 ◽  
Vol 50 (5) ◽  
pp. 1097-1109 ◽  
Author(s):  
Slavomír Bystrický ◽  
Rudolf Kohn ◽  
Tibor Sticzay ◽  
Karel Bláha
Keyword(s):  
Complex Formation ◽  
Electrostatic Interaction ◽  
Polypeptide Chain ◽  
Cd Spectrum ◽  
Esterification Degree ◽  
Circular Dichroic

The circular dichroic (CD) measurement was chosen the tool to investigate the complex formation of poly(L-lysine) with potassium pectate or pectinate of various esterification degree (E). The polycation-polyanion (pectate, E 0%) 1 : 1 complex was quantitatively formed by an electrostatic interaction independently upon the excess of either component. The partial esterification of pectin resulted in a decrease of complex formation; this drop is at a 20% esterification degree low, at higher esterification degrees (46% and 64%) considerable, and at an esterification degree 86% the complex has not been formed at all. The polypeptide chain was present in the complex in an α-helical arrangement characterized by the CD spectrum; the potential spatial arrangements of the complex were proposed. The α-helical polypeptide component constitutes a core surrounded by a superstructure of D-galacturonan chains.

Adsorption of Cu2+ Metal Ions on Dithizone-Immobilized Natural Bentonite

2020 ◽  
Vol 840 ◽  
pp. 64-70
Author(s):  
Dian Mira Fadela ◽  
Mudasir Mudasir ◽  
Adhitasari Suratman
Keyword(s):  
Adsorption Isotherm ◽  
Complex Formation ◽  
Metal Ions ◽  
Electrostatic Interaction ◽  
Metal Ion ◽  
Synthesis And Characterization ◽  
Optimum Conditions ◽  
Initial Concentration ◽  
Activated Bentonite

The research of adsorption of Cu2+ metal ion on dithizone-immobilized natural bentonite (DNB) had been carried out. The experiment was begun by the activation of natural bentonite with HCl 4 M and dithizone-immobilized on activated bentonite surface. This study included synthesis and characterization of dithizone-immobilized bentonite and its application in adsorption of Cu2+ metal ions. The type of interaction occurred in the adsorption was tested by sequential desorption. The result showed that dithizone successfully immobilized on activated natural bentonite (ANB). The optimum conditions for Cu2+ metal ions adsorption using dithizone-immobilized natural bentonite are at pH 5; 0.1 g mass of adsorbent, with interaction time 60 min, and the initial concentration of ion at 80 ppm. Kinetics and adsorption isotherm studies suggest that the capacity, of the dithizone-immobilized natural bentonite in adsorbing Cu2+ metal ion is significantly improved compared to activated natural bentonite. The adsorption of Cu2+ metal ions by activated natural bentonite was through several interactions dominated by electrostatic interaction (82%). Otherwise, the interaction of dithizone-immobilized natural bentonite with Cu2+ metal ions in the sequence were dominated by the mechanism of complex formation of (75%). The result shows that the immobilization of dithizone changes the type of electrostatic interaction into complex formation.

Electrostatic Interaction and Complex Formation between Gum Arabic and Bovine Serum Albumin

2010 ◽  
Vol 11 (12) ◽  
pp. 3367-3374 ◽  
Author(s):  
T. Vinayahan ◽  
P. A. Williams ◽  
G. O. Phillips
Keyword(s):  
Bovine Serum Albumin ◽  
Complex Formation ◽  
Serum Albumin ◽  
Electrostatic Interaction ◽  
Bovine Serum ◽  
Gum Arabic

scholarly journals Formation of Nanocomplexes between Carboxymethyl Inulin and Bovine Serum Albumin via pH-Induced Electrostatic Interaction

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3056 ◽  
Author(s):  
Guiying Huang ◽  
Jun Liu ◽  
Weiping Jin ◽  
Zihao Wei ◽  
Chi-Tang Ho ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Bovine Serum Albumin ◽  
Complex Formation ◽  
Serum Albumin ◽  
Electrostatic Interaction ◽  
Bovine Serum ◽  
Titration Calorimetry ◽  
Food Ingredients ◽  
Enthalpy Changes ◽  
Ft Ir

As a functional polysaccharide, inulin was carboxymethylated and it formed nanocomplexes with bovine serum albumin (BSA). The success of obtaining carboxymethyl inulin (CMI) was confirmed by a combination of Fourier transform Infrared (FT-IR), Raman spectroscopy, gel permeation chromatography (GPC), and titration. The effects of pH and ionic strength on the formation of CMI/BSA nanocomplexes were investigated. Our results showed that the formation of complex coacervate (pHφ1) and dissolution of CMI/BSA insoluble complexes (pHφ2) appeared in pH near 4.85 and 2.00 respectively. FT-IR and Raman data confirmed the existence of electrostatic interaction and hydrogen bonding between CMI and BSA. The isothermal titration calorimetry (ITC) results suggested that the process of complex formation was spontaneous and exothermic. The complexation was dominated by enthalpy changes (∆Η < 0, ∆S < 0) at pH 4.00, while it was contributed by enthalpic and entropic changes (∆Η < 0, ∆S > 0) at pH 2.60. Irregularly shaped insoluble complexes and globular soluble nanocomplexes (about 150 nm) were observed in CMI/BSA complexes at pH 4.00 and 2.60 while using optical microscopy and atomic force microscopy, respectively. The sodium chloride suppression effect on CMI/BSA complexes was confirmed by the decrease of incipient pH for soluble complex formation (or pHc) and pHφ1 under different sodium chloride concentrations. This research presents a new functional system with the potential for delivering bioactive food ingredients.

scholarly journals Differential requirements for polypeptide chain initiation complex formation at the three bacteriophage R17 initiator regions

1977 ◽  
Vol 4 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Joan Argetsinger Steitz ◽  
Albert J. Wahba ◽  
Michael Laughrea ◽  
Peter B. Moore
Keyword(s):  
Complex Formation ◽  
Polypeptide Chain ◽  
Initiation Complex ◽  
Chain Initiation

The nature of the bond-length change upon molecule complexation

2010 ◽  
Vol 75 (3) ◽  
pp. 243-256 ◽  
Author(s):  
Weizhou Wang ◽  
Yu Zhang ◽  
Baoming Ji
Keyword(s):  
Charge Transfer ◽  
Complex Formation ◽  
Bond Length ◽  
Electrostatic Interaction ◽  
Length Change ◽  
Attractive Interaction ◽  
Charge Transfer Interaction ◽  
The Difference ◽  
Hydrogen Bonded

The nature of the bond-length change upon molecule complexation has been investigated at the MP2/aug-cc-pVTZ level of theory. Our results have clearly shown that the X–Y bond-length change upon complex formation is determined mainly by the electrostatic attractive interaction and the charge-transfer interaction. In the case of strongly polar bond, the electrostatic interaction always causes bond elongation while in the case of weakly polar bond it causes bond contraction. The charge-transfer interaction generally results in the X–Y bond elongation; either it is a more polar bond or it is a less polar bond. Employing this simple “electrostatic interaction plus charge-transfer interaction” explanation, we explained and predicted many interesting phenomena related to the bond-length change upon molecule complexation. In addition, the difference between the origin of the bond-length change upon hydrogen-bonded complex formation and the origin of the bond-length change upon halogen-bonded complex formation was also discussed.

The circular dichroism of ovoverdin and other carotenoproteins from the lobster Homarus americanus

1983 ◽  
Vol 61 (9) ◽  
pp. 1018-1024 ◽  
Author(s):  
N. Martin Young ◽  
Ross E. Williams
Keyword(s):  
Visible Region ◽  
Homarus Americanus ◽  
Cd Spectra ◽  
Visible Absorption ◽  
Cd Spectrum ◽  
Negative Band ◽  
Shell Protein ◽  
Fitting Procedures ◽  
Positive Feature ◽  
Circular Dichroic

The circular dichroic (CD) spectra of the α-, β′-, and γ-crustacyanins, ovoverdin, and the yellow lobster-shell protein were measured in the region 200–750 nm, for comparison with the CD spectrum of the free carotenoid astaxanthin. The two carotenoid chromophores of ovoverdin gave a CD spectrum with a series of bands of alternating sign and ellipticities up to 1.9 × 105 degree∙cm2∙dmol−1, comparable to the low temperature CD spectrum of astaxanthin in the UV region. The visible region of ovoverdin also contained strong CD bands where astaxanthin itself has very weak ones. The blue (640 nm) chromophore of ovoverdin gave a broad negative CD feature quite different from the blue chromophores of the three crustacyanins. The crustacyanins have a broad positive feature between 400 and 610 nm with ellipticities up to 2 × 105 degree∙cm2∙dmol−1, followed at higher wavelengths by a negative band with an ellipticity up to 1 × 105 degree∙cm2∙dmol−1. Gaussian curve-fitting procedures showed the positive features to consist of a minimum of two or three CD bands. In addition to the exciton bands at the main visible absorption, the yellow lobster-shell protein had a pair of CD bands of equal but opposite ellipticity associated with an absorption band between 250 and 340 nm. The UV regions of the CD spectra of the five carotenoproteins have bands from both carotenoid and protein chromophores, and possible assignments of these bands to one or the other of the two types of chromophore are proposed.

Complexation of poly(Lys-Ala) and poly(Lys-Ala-Ala-Ala) with pectins and potassium oligogalacturonates

1988 ◽  
Vol 53 (11) ◽  
pp. 2833-2842 ◽  
Author(s):  
Slavomír Bystrický ◽  
Anna Malovíková ◽  
Tibor Sticzay ◽  
Karel Bláha
Keyword(s):  
Charge Density ◽  
Helical Structure ◽  
Local Mode ◽  
Side Chains ◽  
Specific Band ◽  
Esterification Degree ◽  
Superhelical Structure ◽  
Circular Dichroic

The selected model polypeptides poly(Lys-Ala) and poly(Lys-Ala-Ala-Ala) underwent a helix-forming interaction with potassium pectates and pectinates of various esterification degree (E) and with some potassium oligogalacturonates (n = 2-5, 9, 13). Formation of the complex quantitatively monitored by a circular dichroic measurement showed that the specific band distribution of charged side chains of lysine units at the surface of helical structure does not constitute grounds for the local mode of interaction. Potassium pectinate of esterification degree E 57%, corresponding to polypeptides by charge density, does not reveal enhanced complexation values. The complex-forming efficacy continuously decreases with the increase of the esterification degree of pectin. Saturation of charges of the polypeptide was achieved predominantly by the spatial action of the superhelical structure of D-galacturonate chains.

Functional expression of eukaryotic polypeptide chain release factors 1 and 3 by means of baculovirus/insect cells and complex formation between the factors

1998 ◽  
Vol 256 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Lyudmila Y. Frolova ◽  
Janne L. Simonsen ◽  
Tatyana I. Merkulova ◽  
Dmitry Y. Litvinov ◽  
Pia M. Martensen ◽  
...  
Keyword(s):  
Complex Formation ◽  
Insect Cells ◽  
Polypeptide Chain ◽  
Functional Expression ◽  
Release Factors
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