Synthesis of pressinoic acid by enzymatically catalyzed formation of peptide bonds

1986 ◽  
Vol 51 (6) ◽  
pp. 1352-1360 ◽  
Author(s):  
Václav Čeřovský
Keyword(s):  
Methyl Esters ◽  
Sulfhydryl Group ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Peptide Bonds ◽  
Fragment Condensation

Three fully enzymatic syntheses of the 1-6 vasopressin hexapeptide were investigated using papain, α-chymotrypsin and thermolysin. Best results were obtained with thermolysin in the 2 + 4 fragment condensation. The α-chymotrypsin-catalyzed 3 + 3 condensation is less advantageous and the 4 + 2 condensation with papain gave only low yield. Using the mentioned enzymes, further fragments of vasopressin molecule were prepared. Amino groups were protected with benzoylcarbonyl or tert-butyloxycarbonyl groups, carboxyl groups as phenylhydrazides or methyl esters, and the cysteine sulfhydryl group as the benzyl derivate. The tyrosine hydroxyl was not protected.

scholarly journals Positive Charges on Lysine Residues of the Extrinsic 18 kDa Protein Are Important to Its Electrostatic Interaction with Spinach Photosystem II Membranes

2005 ◽  
Vol 37 (11) ◽  
pp. 737-742 ◽  
Author(s):  
Jin-Peng Gao ◽  
Zhen-Hua Yong ◽  
Feng Zhang ◽  
Kang-Cheng Ruan ◽  
Chun-He Xu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Methyl Esters ◽  
Binding Activity ◽  
Water Soluble ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Charged Amino Acids ◽  
Lysine Residues ◽  
Glycine Methyl Ester ◽  
Positively Charged

Abstract To determine the contribution of charged amino acids to binding with the photosystem II complex (PSII), the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with Nsuccinimidyl propionate (NSP) or glycine methyl ester (GME) in the presence of a water-soluble carbodiimide, respectively. Based on isoelectric point shift, 4–10 and 10–14 amino groups were modified in the presence of 2 and 4 mM NSP, respectively. Similarly, 3–4 carboxyl groups were modified by reaction with 100 mM GME. Neutralization of negatively charged carboxyl groups with GME did not alter the binding activity of the extrinsic 18 kDa protein. However, the NSP-modified 18 kDa protein, in which the positively charged amino groups had been modified to uncharged methyl esters, failed to bind with the PSII membrane in the presence of the extrinsic 23 kDa protein. This defect can not be attributed to structural or conformational alterations imposed by chemical modification, as the fluorescence and circular dichroism spectra among native, GME and NSP-modified extrinsic 18 kDa proteins were similar. Thus, we have concluded that the positive charges of lysyl residues in the extrinsic 18 kDa protein are important for its interaction with PSII membranes in the presence of the extrinsic 23 kDa protein. Furthermore, it was found that the negative charges of carboxyl groups of this protein did not participate in binding with the extrinsic 23 kDa protein associated with PSII membranes.

Enzymatically catalyzed synthesis of oxytocin fragments 1-6 and 7-9

1985 ◽  
Vol 50 (12) ◽  
pp. 2775-2782 ◽  
Author(s):  
Václav Čeřovský ◽  
Karel Jošt
Keyword(s):  
Ethyl Ester ◽  
Sulfhydryl Group ◽  
Amino Groups ◽  
Equimolar Ratio ◽  
Peptide Bonds ◽  
The Given

Papain, α-chymotrypsin, thermolysin and elastase were utilized in the synthesis of peptide bonds of the protected oxytocin nonapeptide, except the S-benzylcysteine-proline bond. Amino groups were protected with benzyloxycarbonyl or tert-butyloxycarbonyl groups, carboxy groups as ethyl ester, phenylhydrazides or amides. The cysteine sulfhydryl group was blocked with the benzyl group whereas the tyrosine hydroxyl was unprotected. Most of the fragments were synthesized in satisfactory yields using an equimolar ratio of both reaction components and minimal (experimentally determined) amount of the given enzyme.

scholarly journals The principle of formaldehyde, alcohol, and acetone titrations. With a discussion of the proof and implication of the zwitterion conception

1934 ◽  
Vol 115 (792) ◽  
pp. 121-141 ◽  
Keyword(s):  
Amino Acids ◽  
Carboxyl Groups ◽  
Recent Discussion ◽  
Amino Groups ◽  
Chemical Methods ◽  
Titration Method ◽  
Physico Chemical ◽  
Empirical Argument ◽  
Chemical Evidence

Consideration of the implications of the zwitterion hypothesis of Bjerrum (1923) makes it desirable to state afresh the principles underlying the methods commonly employed in the titration of amino-acids. Deductions of considerable theoretical importance, cf., e. g ., Calvery (1933) are still being made on the supposition that the alkalimetric formaldehyde titration method of Sørensen (1907) and the corresponding alcohol method of Foreman (1920) and of Willstätter and Waldschmidt-Leitz (1921) estimate the carboxyl groups of amino-acids whilst the acidimetric acetone titration of Linderstrøm-Lang (1928) estimates the amino-groups. Yet the zwitterion hypothesis indicates that this assumption is the reverse of the truth. Discussion is greatly facilitated by collective consideration of recent physico-chemical evidence clarifying the principles upon which these common bio-chemical methods rest. In a recent discussion of two of the titrimetric methods (Van Slyke and Kirk, 1933) the existence of this evidence is ignored, so that it becomes necessary to systematize and elaborate the empirical argument of these authors in the light of the relevant investigations of Grünhut (1919), Cray and Westrip (1925), Michaelis and Mizutani (1925), Birch and Harris (1930, b ), and Levy (1933). At the same time new and useful developments are indicated.

scholarly journals Isolation, purification and structure of exochelin MS, the extracellular siderophore from Mycobacterium smegmatis

1995 ◽  
Vol 305 (1) ◽  
pp. 187-196 ◽  
Author(s):  
G J Sharman ◽  
D H Williams ◽  
D F Ewing ◽  
C Ratledge
Keyword(s):  
Amino Acids ◽  
Mycobacterium Smegmatis ◽  
Methyl Esters ◽  
Three Dimensional ◽  
Iron Chelation ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Gallium Complex

The extracellular siderophore from Mycobacterium smegmatis, exochelin MS, was isolated from iron-deficiently grown cultures and purified to > 98% by a combination of ion-exchange chromatography and h.p.l.c. The material is unextractable into organic solvents, is basic (pI = 9.3-9.5), has a lambda max at 420 nm and a probable Ks for Fe3+ of between 10(25) and 10(30). Its structure has been determined by examination of desferri- and ferri-exochelin and its gallium complex. The methods used were electrospray-m.s. and one- and two-dimensional (NOESY, DQF-COSY and TOCSY) 1H n.m.r. The constituent amino acids were examined by chiral g.l.c analysis of N-trifluoroacetyl isopropyl and N-pentafluoropropionyl methyl esters after hydrolysis, and reductive HI hydrolysis, of the siderophore. The exochelin is a formylated pentapeptide: N-(delta-N-formyl,delta N-hydroxy-R-ornithyl) -beta-alaninyl-delta N-hydroxy-R-ornithinyl-R-allo-threoninyl-delta N-hydroxy-S-ornithine. The linkages involving the three ornithine residues are via their delta N(OH) and alpha-CO groups leaving three free alpha-NH2 groups. Although there are two peptide bonds, these involve the three R (D)-amino acids. Thus the molecule has no conventional peptide bond, and this suggests that it will be resistant to peptidase hydrolysis. The co-ordination centre with Fe3+ is hexadenate in an octahedral structure involving the three hydroxamic acid groups. Molecular modelling shows it to have similar features to other ferric trihydroxamate siderophores whose three-dimensional structures have been established. The molecule is shown to have little flexibility around the iron chelation centre, although the terminal (Orn-3) residue, which is not involved in iron binding except at its delta N atom, has more motional freedom.

STRUCTURE ACTIVITY RELATIONSHIPS OF DERMATAN SULFATE : EFFECT OF MOLECULAR SIZE AND CARBOXYL GROUP ESTERIFICATION ON HEPARIN C0FACT0R-II ACTIVATION

1987 ◽  
Author(s):  
J Mardiguian ◽  
M Corgier ◽  
M Jouany
Keyword(s):  
Molecular Weight ◽  
Dermatan Sulfate ◽  
Methyl Esters ◽  
Molecular Size ◽  
Carboxyl Groups ◽  
Gel Chromatography ◽  
Carboxyl Group ◽  
Heparin Cofactor Ii ◽  
High Affinity

Dermatan is a high molecular weight glycosaminoglycan which has been shown to enhance the inhibition of thrombin by heparin-cofactor II. The aim of this study was to establish the influence of the molecular size and the role of the carboxyl group on the in vitro activity of Dermatan Sulfate. Pig skin Dermatan Sulfate was fractionated according to molecular size by gel-chromatography on Ultrogel Ac 44. Each fraction was characterized by its sulfur content and by its mean molecular weight measured on a TSK - 4000 column in reference to standard heparin fractions. Methyl esters of the unfractionated Dermatan Sulfate with varying degree of esterification, where prepared via activation of the carboxyl groups with a carbodiimide and reaction with methanol. The results of this study show that the heparin - cofactor II mediated anti-thrombin activity of Dermatan Sulfate is increasing with the molecular weight and is abolished by esterification of the carboxyl groups. Moreover, it can be speculated that each fraction contains the same amount of high affinity fraction and that, like heparin, the potency of the high affinity component is increasing with the molecular weight.

Self-assembly of strawberry-like organic–inorganic hybrid particle clusters with directionally distributed bimetal and facile transformation of the core and corona

2020 ◽  
Vol 11 (18) ◽  
pp. 3136-3151 ◽  
Author(s):  
Shuxing Mei ◽  
Mingwang Pan ◽  
Juan Wang ◽  
Xiaopeng Zhang ◽  
Shaofeng Song ◽  
...  
Keyword(s):  
Strong Interaction ◽  
Self Assembly ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Inorganic Hybrid ◽  
Inorganic Particles ◽  
Hybrid Particle ◽  
The Core ◽  
Organic Particles ◽  
Facile Transformation

Controllable structure of organic–inorganic hybrid particle clusters were successfully fabricated by self-assembly which derived from the strong interaction between carboxyl groups of the organic particles and amino groups of the inorganic particles.

scholarly journals Specific reduction of carboxyl groups in peptides and proteins by diborane

1969 ◽  
Vol 111 (4) ◽  
pp. 593-601 ◽  
Author(s):  
M. Z. Atassi ◽  
Arthur F. Rosenthal
Keyword(s):  
Cyclic Peptides ◽  
Acid Amide ◽  
Sperm Whale ◽  
Biological Properties ◽  
Carboxyl Groups ◽  
Peptide Bonds ◽  
Human Haemoglobin ◽  
Horse Heart Cytochrome ◽  
Egg White Lysozyme ◽  
Horse Heart Cytochrome C

1. The reaction of several peptides and proteins with diborane was studied under different conditions to determine those most suitable for the specific reduction of carboxyl groups. 2. In the reaction of model peptides and the cyclic peptides bacitracin and tyrocidin, reduction at 0° was entirely specific for the carboxyl groups without affecting the peptide bonds. Acid amide residues were not reduced. Some tripeptides showed anomalous results in that the C-terminal residue was quite resistant to reduction. 3. Specific reduction of carboxyl groups was achieved in each of the following proteins: human serum albumin, egg albumin, adult human haemoglobin, sperm-whale apomyoglobin, horse heart cytochrome c and egg-white lysozyme. The C-terminal amino acid was usually reduced. 4. Conditions for specific reduction of all available carboxyl groups are not easily found and may vary from one substance to another. Specific reduction of a limited number of available carboxyl groups may be generally accomplished by reactions at −10°. 5. It is suggested that this chemical modification, which has the advantage of permanence, may be useful in studying the role of carboxyl groups in the conformation of proteins and in the biological properties of peptides and proteins.

Highly selective and sensitive biosensing of dopamine based on glutathione coated silver nanoclusters enhanced fluorescence

2017 ◽  
Vol 41 (24) ◽  
pp. 15244-15250 ◽  
Author(s):  
Ramar Rajamanikandan ◽  
Malaichamy Ilanchelian
Keyword(s):  
Hydrogen Bonding ◽  
Emission Intensity ◽  
Silver Nanoclusters ◽  
Carboxyl Groups ◽  
Hydrogen Bonding Interaction ◽  
Amino Groups ◽  
Enhanced Fluorescence ◽  
Bonding Interaction

The emission intensity of red emissive GSH-AgNCs is notably enhanced after the addition of dopamine. The increasing emission intensity is attributed to the hydrogen bonding interaction between the carboxyl groups of GSH-AgNCs and amino groups of dopamine.

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