scholarly journals Acetoacetylation of insulin

1969 ◽  
Vol 115 (3) ◽  
pp. 587-595 ◽  
Author(s):  
D. G. Lindsay ◽  
S. Shall
Keyword(s):  
Tertiary Structure ◽  
Group Analysis ◽  
Amino Group ◽  
Hormonal Activity ◽  
Fourth Component ◽  
End Group

Insulin was treated with diketen at pH6·9. The reaction mixture was resolved into four components by DEAE-Sephadex chromatography. The first component was unchanged insulin. The second and third components were shown by end-group analysis to be substituted on phenylalanine B-1 and glycine A-1 respectively. The fourth component was disubstituted on both phenylalanine B-1 and glycine A-1. The ∈-amino group of lysine B-29 was not involved in the reaction at low reagent concentrations. The purity of these derivatives was checked by their electrophoretic behaviour and by measurement of the rate of their reaction with trinitrobenzenesulphonic acid. The hormonal activity of the derivatives was determined. The effect of the modifications on the hormonal activity and the tertiary structure of insulin is discussed.

scholarly journals The acetylation of insulin

1971 ◽  
Vol 121 (5) ◽  
pp. 737-745 ◽  
Author(s):  
D. G. Lindsay ◽  
S. Shall
Keyword(s):  
Biological Activity ◽  
Free Amino ◽  
Tertiary Structure ◽  
Group Analysis ◽  
Insulin Antibodies ◽  
The Other ◽  
Amino Group ◽  
Amino Groups ◽  
Chloromethyl Ketone ◽  
End Group

The acetylation of the free amino groups of insulin was studied by reaction of the hormone with N-hydroxysuccinimide acetate at pH6.9 and 8.5. The products formed were separated by chromatography on DEAE-Sephadex and were characterized by isoelectric focusing, by end-group analysis, by the incorporation of [3H]acetyl groups in the molecule, and by treatment with trypsin that had been treated with 1-chloro-4-phenyl-3-toluene-p-sulphonamidobutan-2-one (‘tosylphenylalanyl chloromethyl ketone’). Three monosubstituted products, two disubstituted products and one trisubstituted derivative were prepared. The α-amino groups of the terminal residues and the ∈-amino group of the lysine-B29 were the sites of reaction. Acetylation of any of the free amino groups did not affect the biological activity of insulin. It was demonstrated, however, that substitution at the glycine-A1 amino group by the larger residues, acetoacetyl or thiazolidinecarbonyl, produced a decrease in biological activity. Modification of the lysine-B29 or phenylalanine-B1 amino groups with these larger reagents did not affect the biological activity. Modification of the phenylalanine-B1 amino group by any of the three substituents resulted in a large decrease in the affinity of insulin for anti-insulin antibodies raised in the guinea pig. Modification of the other two amino groups did not affect the reaction with antibody. These observations are correlated with the tertiary structure of insulin.

Isolierung und Identifizierung eines serinhaltigen UDP-muramyl-tripeptides aus Butyribacterium rettgeri

1968 ◽  
Vol 23 (2) ◽  
pp. 217-220 ◽  
Author(s):  
I. Miller ◽  
R. Plapp ◽  
O. Kandler
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Glutamic Acid ◽  
Group Analysis ◽  
Partial Hydrolysis ◽  
Carboxyl Group ◽  
Amino Group ◽  
Muramic Acid ◽  
End Group

An UDP-activated murein precursor was isolated from Butyribacterium rettgeri after one hour inhibition by D-cycloserine. The compound contains UDP, muramic acid, L-serine, D-glutamic acid and L-ornithine in equimolar amounts. The amino acid sequence of the tripeptide attached to muramic acid is L-Ser-D-Glu-L-Orn as determined by end group analysis and identification of peptides obtained after partial hydrolysis. As shown by the identification of glutamic acid -γ-hydrazid after hydrazinolysis of the compound, ornithine is bound by its α-amino group to the γ-carboxyl group of glutamic acid. The amino acid sequence of the precursor is in agreement with the structure of the corresponding part of the whole murein of Butyribacterium rettgeri, as proposed recently.

scholarly journals THE ISOTOPE DERIVATIVE METHOD OF PROTEIN AMINO END-GROUP ANALYSIS

1951 ◽  
Vol 190 (2) ◽  
pp. 733-740 ◽  
Author(s):  
Sidney. Udenfriend ◽  
Sidney F. Velick
Keyword(s):  
Group Analysis ◽  
Derivative Method ◽  
End Group

scholarly journals Genetic Polymorphism in Caseins of Cow's Milk. V. End-Group Analysis of β-Caseins A, B, and C

1965 ◽  
Vol 48 (7) ◽  
pp. 884-887 ◽  
Author(s):  
E.B. Kalan ◽  
M.P. Thompson ◽  
Rae Greenberg ◽  
L. Pepper
Keyword(s):  
Genetic Polymorphism ◽  
Group Analysis ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
End Group

scholarly journals Sizing and Thermal Stability of Prepared Tetraaminophthalocyaninatocopper(II) Derivatives-grafted Polymers

2016 ◽  
Vol 13 (2) ◽  
pp. 221-234
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Group Analysis ◽  
Condensation Polymerization ◽  
Grafted Polymers ◽  
Poly Ethylene Glycol ◽  
Molecular Weights ◽  
Poly Ethylene ◽  
Thermal Stability Of ◽  
End Group

Different polymers were prepared by condensation polymerization of sebacic anhydride and adipic anhydride with ethylene glycol and poly(ethylene glycol). Their number average molecular weights were determined by end group analysis. Then, they were grafted on the prepared phthalocyaninatocopper(II) compounds with the general formula (NH2)4PcCu(II) having amino groups of 3,3',3'',3'''- or 4,4',4'',4'''- positions. All prepared polymers, compounds, and phthalocyaninatocopper(II)-grafted polymers were characterized by FTIR. The sizing measurements were carried out in 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) compounds with and without grafting polymers. The results showed that the grafting process led to decreasing in particle size and increasing in surface area. The grafting process was reflected positively on the thermal degradation of 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) grafted polymers. They had higher thermal stability accompanied with higher char residue and T50% weight loss with 3,3',3'',3'''-(NH2)4PcCu(II) and their grafted polymers being the best.

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