Mass spectra of methoxy-substituted methyl esters of benzenecarboxylic acids with different numbers of carboxyl groups

1983 ◽  
Vol 32 (9) ◽  
pp. 1858-1866
Author(s):  
V. N. Galyashin ◽  
Yu. N. El'kin ◽  
B. V. Rozynov ◽  
N. M. Kuz'min
Keyword(s):  
Mass Spectra ◽  
Methyl Esters ◽  
Carboxyl Groups ◽  
Benzenecarboxylic Acids

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.

Mass spectra of diterpene resin acid methyl esters

1971 ◽  
Vol 48 (9) ◽  
pp. 455-461 ◽  
Author(s):  
Teh-Liang Chang ◽  
Thomas E. Mead ◽  
Duane F. Zinkel
Keyword(s):  
Mass Spectra ◽  
Methyl Esters ◽  
Resin Acid ◽  
Acid Methyl

Electron impact studies. LXXVIII. Rearrangement ions and proximity effects in the 'doubly charged ion' mass spectra of benzoic acid derivatives

1973 ◽  
Vol 26 (1) ◽  
pp. 195 ◽  
Author(s):  
JH Bowie
Keyword(s):  
Benzoic Acid ◽  
Mass Spectra ◽  
General Feature ◽  
Molecular Ions ◽  
Ring System ◽  
Proximity Effects ◽  
Carboxyl Groups ◽  
Benzoic Acids ◽  
Benzoic Acid Derivatives ◽  
Doubly Charged

The technique of Beynon1,2 has been used to determine the ?doubly charged ion? mass spectra of a series of benzoic acid derivatives. A general feature of all spectra is the presence of pronounced M-CO species. The losses of carbon monoxide from the doubly charged molecular ions of m- amino- and m-hydroxy-benzoic acids originate mainly from the carboxyl groups, whereas the predominant loss from benzoic acid involves the aryl ring system. The spectra of anthranilates and salicylates contain peaks produced by characteristic proximity effects.

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.

scholarly journals Precambrian organic compounds from the Ketilidian of South-West Greenland. Part III

1970 ◽  
Vol 82 ◽  
pp. 1-42
Author(s):  
K.R Pedersen ◽  
J Lam
Keyword(s):  
Fatty Acids ◽  
Organic Compounds ◽  
Homologous Series ◽  
Mass Spectra ◽  
Methyl Esters ◽  
Graphite Layer ◽  
Straight Chain ◽  
Normal Alkanes ◽  
Cyclic Hydrocarbons ◽  
Alkyl Benzenes

Ketilidian sedimentary rocks nearly 2000 m.y. old and only slightly metamorphosed have been shown to contain fossils and organic compounds. Results of work on organic material from a 1-3 m thick coal-graphite layer from the Foselv Formation in the Sortis Group in Grænseland are presented. Aliphatic (straight chain, branched and cyclic) hydrocarbons are dominant in the extract from two coal-graphite samples weighing about 4 kg and 10 kg respectively. Further investigations of these compounds have revealed many saturated straight-chain hydrocarbons, with the n-C15 alkane, the most abundant among the normal alkanes, ranging from C12 to about C21, and various isoalkanes and anteisoalkanes. Saturated cyclic hydrocarbons like alkyl cyclohexanes, and homologous series of alkyl benzenes and alkyl naphthalenes are also present. A series of monoterpenoid compounds is present. Six of them are fairly well characterized by their mass spectra. Fatty acids and methyl esters of fatty acids are present, notably a homologous series of straight-chain fatty acids. Branched acids are also present in minor amounts. The organic compounds further indicate that this Precambrian coal-graphite layer is the result of biological activity.

Mass spectra of methyl esters of brominated fatty acids and their presence in soft drinks and cocktail syrups

2013 ◽  
Vol 27 (9) ◽  
pp. 1083-1089 ◽  
Author(s):  
Paul Bendig ◽  
Lisa Maier ◽  
Katja Lehnert ◽  
Holger Knapp ◽  
Walter Vetter
Keyword(s):  
Fatty Acids ◽  
Mass Spectra ◽  
Methyl Esters ◽  
Soft Drinks

Spectroscopic Properties of the Methyl Esters of Chlorophenoxy Acid Herbicides

1975 ◽  
Vol 58 (5) ◽  
pp. 1001-1012 ◽  
Author(s):  
Carlos H Van Peteghem ◽  
Aubin M Heyndrickx
Keyword(s):  
Magnetic Resonance ◽  
Infrared Spectra ◽  
Proton Magnetic Resonance ◽  
Mass Spectra ◽  
Methyl Esters ◽  
Spectroscopic Properties ◽  
Chlorophenoxy Acid Herbicides ◽  
Acid Herbicides ◽  
Magnetic Resonance Spectra

Abstract The mass and infrared spectra of the methyl esters of 9 chlorophenoxy acid herbicides are presented. Ultraviolet data are discussed and proton magnetic resonance spectra are tabulated. Because of the sensitivity of the technique, the mass spectra are most useful for the identification of those compounds in residues, especially by combined gas chromatographymass spectrometry. The pure herbicides used for the recording of the spectra were obtained by synthesis and recrystallization.

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