scholarly journals Preparation and activity of guanidinated or acetylated erabutoxins

1976 ◽  
Vol 153 (2) ◽  
pp. 217-222 ◽  
Author(s):  
H Hori ◽  
N Tamiya
Keyword(s):  
Circular Dichroism ◽  
Acetic Anhydride ◽  
Column Chromatography ◽  
Reaction Products ◽  
Amino Groups ◽  
Sea Snake ◽  
Lysine Residues ◽  
Erabutoxin B ◽  
Circular Dichroïsm

1. Erabutoxins, a, b and c, neurotoxic proteins of a sea snake Lacticauda semifasciata, were guanidinated with O-methylisourea. The amino groups of all the lysine residues and those at the N-termini of the toxins were modified. The lethal activity of the toxins decreased to 50% (erabutoxins a and b) or 17% (erabutoxin c) of the original value on the modification. The c.d. (circular dichroism) maximum at 227 nm of the modified toxins became lower, whereas the whole profile of the c.d. curve remained unchanged. 2. The amino groups of erabutoxin b were acetylated with acetic anhydride. All the five monoacetyl derivatives were isolated from the reaction products by CM-cellulose and Bio-Rex 70 column chromatography. [1-Nalpha-acetylarginine]-, [15-N6-acetyl-lysine]- and [51-N6-acetyl-lysine]-erabutoxin b retained the toxicity of the native toxin, whereas [27-N6-acetyl-lysine] and [47-N6-acetyl-lysine]-erabutoxin b were 17 and 8% active respectively. The overall profile of c.d. spectrum of erabutoxin b remained unchanged on the monoacetylation.

scholarly journals Isoelectric points of erabutoxins and monoacyl derivatives of erabutoxin b. Estimation of the pK values of amino groups in erabutoxins by using isoelectric-focusing data

1982 ◽  
Vol 203 (2) ◽  
pp. 427-433 ◽  
Author(s):  
N UI ◽  
C Takasaki ◽  
N Tamiya
Keyword(s):  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Amino Group ◽  
Amino Groups ◽  
Sea Snake ◽  
Isoelectric Points ◽  
Point Data ◽  
Laticauda Semifasciata ◽  
Erabutoxin B ◽  
Derivatives Of

The isoelectric points of erabutoxins a, b and c, neurotoxic proteins of a sea snake, Laticauda semifasciata, were determined by density-gradient isoelectric focusing. The same measurement was also made with monoacyl derivatives of erabutoxin b, in which each one of all amino groups had been either acetylated or propionylated. Erabutoxins a and b showed the same isoelectric point at pH 9.68. The values for [1-N alpha-acetyl-arginine]-, [15-N6-acetyl-lysine]-, [27-N6-acetyl-lysine]-, [47-N6-propionyl-lysine]- and [51-N6-acetyl-lysine]-erabutoxin b were at pH 9.52, 9.31, 9.45, 9.22 and 9.09 respectively, being definitely different from each other and lower than the value for the unmodified molecule. The isoelectric point of erabutoxin c, which is [51-asparagine]-erabutoxin b, was the same as that of [51-N6-acetyl-lysine]erabutoxin b. Assuming that no change in pK occurs on monoacylation, the pK values of amino groups in erabutoxin b were calculated from the isoelectric-point data. It is indicated that the pK values of zeta-amino groups differ markedly from each other and that the value of alpha-amino group is anomalously high.

Stereospecific analysis of lorazepam in plasma by chiral column chromatography with a circular dichroism-based detector

2000 ◽  
Vol 871 (1-2) ◽  
pp. 181-188 ◽  
Author(s):  
Hideko Kanazawa ◽  
Yuko Kunito ◽  
Yoshikazu Matsushima ◽  
Shigeo Okubo ◽  
Fumiko Mashige
Keyword(s):  
Circular Dichroism ◽  
Column Chromatography ◽  
Stereospecific Analysis ◽  
Chiral Column ◽  
Circular Dichroïsm

Letter: Specific Isotope Labeling for the Identification of Free N-Terminal Peptides of Proteins Separated by Polyacrylamide Gel Electrophoresis

2007 ◽  
Vol 13 (4) ◽  
pp. 307-309 ◽  
Author(s):  
Aniel Sanchez ◽  
Yassel Ramos ◽  
Yanni Solano ◽  
Luis Javier González ◽  
Lazaro Betancourt ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Gel Electrophoresis ◽  
Isotope Labeling ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Amino Groups ◽  
Ion Distribution ◽  
Lysine Residues ◽  
Primary Amino ◽  
The Difference

We report here a method for the identification of free N-terminal peptides of in gel digested isolated proteins. It is based on the difference between the isotopic ion distribution of the N-terminal peptide and internal peptides. After guanidination of lysine residues, the primary amino groups of the gel-entrapped protein are blocked with an equimolar mixture of normal and deuterated acetic anhydride. Upon MS analysis, internal peptides display a normal isotopic ion distribution while the N-terminal peptide shows a complex isotopic ion distribution.

scholarly journals Reactivity and Ionization Constants of the Lysine Residues in Apovitellenin I of Emu Egg Yolk Low-density Lipoprotein by Competitive Labelling

1975 ◽  
Vol 28 (6) ◽  
pp. 433
Author(s):  
Theo AA Dopheide
Keyword(s):  
Acetic Anhydride ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Egg Yolk ◽  
Ionization Constants ◽  
Low Density ◽  
Amino Groups ◽  
Ph Values ◽  
Titration Curves ◽  
Lysine Residues

Competitive labelling with [14C]acetic anhydride over a range of pH values has been used to explore the surface topography of the apovitellenin I moiety in emu egg yolk low-density lipoprotein. The reaction of the lysine e-amino groups with acetic anhydride has been related to pH in a set of titration curves; from these, the reactivities relative to alanine and the ionization constants of all but the amino terminallysines have been determined.

scholarly journals Three New Phthalide Glycosides from the Rhizomes of Cnidium officinale and Their Recovery Effect on Damaged Otic Hair Cells in Zebrafish

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 7034
Author(s):  
Hyoung-Geun Kim ◽  
Seon Min Oh ◽  
Na Woo Kim ◽  
Ji Heon Shim ◽  
Youn Hee Nam ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Column Chromatography ◽  
Hair Cells ◽  
Spectroscopic Data ◽  
Recovery Effect ◽  
Active Fraction ◽  
Chemical Structures ◽  
Cnidium Officinale ◽  
Circular Dichroïsm

The extract from Cnidium officinale rhizomes was shown in a prior experiment to markedly recover otic hair cells in zebrafish damaged by neomycin. The current study was brought about to identify the principal metabolite. Column chromatography using octadecyl SiO2 and SiO2 was performed to isolate the major metabolites from the active fraction. The chemical structures were resolved on the basis of spectroscopic data, including NMR, IR, MS, and circular dichroism (CD) data. The isolated phthalide glycosides were assessed for their recovery effect on damaged otic hair cells in neomycin-treated zebrafish. Three new phthalide glycosides were isolated, and their chemical structures, including stereochemical characteristics, were determined. Two glycosides (0.1 μM) showed a recovery effect (p < 0.01) on otic hair cells in zebrafish affected by neomycin ototoxicity. Repeated column chromatography led to the isolation of three new phthalide glycosides, named ligusticosides C (1), D (2), and E (3). Ligusticoside C and ligusticoside E recovered damaged otic hair cells in zebrafish.

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

Circular dichroism spectra of adsorbed dye-aggregates

1968 ◽  
Vol 65 ◽  
pp. 146-151 ◽  
Author(s):  
G. Scheibe ◽  
O. Wörz ◽  
F. Haimerl ◽  
W. Seiffert ◽  
J. Winkler
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm
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