scholarly journals The chemistry of the collagen cross-links. The characterization of Fraction C, a possible artifact produced during the reduction of collagen fibres with borohydride

1973 ◽  
Vol 135 (4) ◽  
pp. 657-665 ◽  
Author(s):  
Simon P. Robins ◽  
Allen J. Bailey
Keyword(s):  
Aldol Condensation ◽  
Condensation Product ◽  
Reduced Form ◽  
Borohydride Reduction ◽  
Cross Link ◽  
Collagen Fibres ◽  
Isolation And Identification ◽  
Cross Links

The present paper describes the isolation and identification of a major radioactive component of borotritide-reduced collagen, previously designated Fraction C. The derived structure for the compound confirms that it is identical with the ‘post-histidine’ component described by Tanzer et al. (1973) and given the trivial name histidino-hydroxymerodesmosine. Detailed studies of the effects of acid pH on the formation of Fraction C after borohydride reduction demonstrated the apparent lability of the non-reduced form, thus confirming our previous findings (Bailey & Lister, 1968). Inhibition of the formation of this component by the acid treatment appears to be due to protonation of the histidine imidazole group. Since the only new component formed on reduction of the acid-treated fibres was the reduced aldol condensation product, these results indicate that neither the histidine nor the hydroxylysine residues can be involved in covalent linkage with the aldol condensation product in the native fibre. It is suggested therefore that the proposed non-reduced aldimine form of Fraction C does not exist as an intermolecular cross-link in vivo. Thus the presence of histidino-hydroxymerodesmosine as a tetrafunctional cross-link in reduced collagen fibres is a result of a base-catalysed reaction promoted by the borohydride-reduction procedure and this component must therefore be considered as an artifact.

scholarly journals The chemistry of the collagen cross-links. The absence of reduction of dehydrolysinonorleucine and dehydrohydroxylysinonorleucine in vivo

1971 ◽  
Vol 121 (2) ◽  
pp. 257-259 ◽  
Author(s):  
A. J. Bailey ◽  
Catherine M. Peach
Keyword(s):  
Soft Tissues ◽  
Cross Link ◽  
Collagen Fibres ◽  
Cross Links

Two aldimine bonds have been shown to be present as stabilizing cross-links in intact collagen fibres from soft tissues: dehydrohydroxylysinonorleucine as a major component and dehydrolysinonorleucine being present in trace quantities. In the highly insoluble collagens less dehydrohydroxylysinonorleucine is present but the proportion of dehydrolysinonorleucine increases. In elastin the latter aldimine is reduced in vivo to give a more stable cross-link but no comparable reduction could be detected with either of the aldimines present in collagen.

scholarly journals The influence of 1-hydroxyethane-1,1-diphosphonate and dichloromethanediphosphonate on lysine hydroxylation and cross-link formation in rat bone, cartilage and skin collagen

1981 ◽  
Vol 196 (1) ◽  
pp. 303-310 ◽  
Author(s):  
H L Guenther ◽  
H E Guenther ◽  
H Fleisch
Keyword(s):  
Condensation Product ◽  
Bone Collagen ◽  
Cross Link ◽  
Skin Collagen ◽  
Cross Links ◽  
The Cross ◽  
Lysine Hydroxylation ◽  
And Cartilage ◽  
Rat Bone

The effects in vivo of dichloromethanediphosphonate and 1-hydroxyethane 1,1-diphosphonate on collagen solubility, hydroxylation of lysine and proline and on the formation of collagen intermolecular cross-links were studied by using rat bone, cartilage and skin tissues. Dichloromethanediphosphonate decreased bone collagen solubility both in acetic acid and after pepsin treatment. Although none of the diphosphonates had any effect on the hydroxylation of proline, dichloromethane-diphosphonate, but not 1-hydroxyethane-1,1-diphosphonate, increased the number of hydroxylysine residues in the alpha-chains of bone, skin and cartilage collagen. The stimulatory effect was dose-dependent. The dichloromethanediphosphonate-mediated increase in hydroxylysine residues in bone and cartilage was manifested in an increase of dihydroxylysinonorleucine, the cross-link that is formed by the condensation of two hydroxylysine residues. The cross-link hydroxylysinonorleucine, a condensation product of hydroxylysine and lysine, on the other hand, was decreased. The total number of intermolecular cross-links was not changed by the diphosphonate.

scholarly journals The chemistry of the collagen cross-links. Characterization of the products of reduction of skin, tendon and bone with sodium cyanoborohydride

1977 ◽  
Vol 163 (2) ◽  
pp. 339-346 ◽  
Author(s):  
S P Robins ◽  
A J Bailey
Keyword(s):  
Mass Spectrometry ◽  
Time Course ◽  
Chemical Degradation ◽  
Reduced Form ◽  
Intermolecular Bond ◽  
Sodium Cyanoborohydride ◽  
Cross Links

Reduction of tissues with sodium cyanoborohydride at pH7.4 gave results identical with those obtained by KBH4 treatment. On reduction with sodium cyanoborohydride at pH 4.4, however, a previously undetected basic compound was formed and was identified by mass spectrometry and chemical degradation techniques as dihydrohydroxymerodesmosine. Histidino-hydroxymerodesmosine was not present, and further analysis confirmed that reduced aldol, a mojor product of reduction with KBH4 at the lower pH, was also absent. These results, together with an analysis of the time course of the reduction, support previous assertions that histidino-hydroxymerodesmosine is an artifact [robins *Bailey (1973) Biochem. J. 135, 657-665] and suggests that the non-reduced form of hydroxymerodesmosine probably does not constitute a major intermolecular bond in vivo.

scholarly journals Chemistry of the collagen cross-links. Isolation and characterization of two intermediate intermolecular cross-links in collagen

1970 ◽  
Vol 117 (5) ◽  
pp. 819-831 ◽  
Author(s):  
A. J. Bailey ◽  
Catherine M. Peach ◽  
L. J. Fowler
Keyword(s):  
Mass Spectrometry ◽  
Large Scale ◽  
High Resolution Mass Spectrometry ◽  
Collagen Fibre ◽  
Reduced Form ◽  
Cross Link ◽  
Isolation And Characterization ◽  
Cross Links

This paper describes the isolation from reduced collagen of two new amino acids believed to be involved, in their non-reduced form, as intermolecular cross-links stabilizing the collagen fibre. The reduction of intact collagen fibrils with tritiated sodium borohydride was found to stabilize the aldehyde-mediated cross-links to acid hydrolysis and thus allowed their location and isolation from acid hydrolysates on an automatic amino acid analyser. Comparison of the radioactive elution patterns from the autoanalyser of collagen treated in various ways before reduction permitted a preliminary classification of the peaks into cross-link precursors, intramolecular and intermolecular cross-links. The techniques employed to isolate the purified components on a large scale and to identify them structurally are described in detail. Two labile intermolecular cross-links were isolated in their reduced forms, one of which was identified by high-resolution mass spectrometry as N∈-(5-amino-5-carboxypentyl)hydroxylysine. The structure of this compound was confirmed by chemical synthesis. The cross-link precursor α-aminoadipic δ-semialdehyde was isolated in its reduced form, ∈-hydroxynorleucine, together with its acid degradation product ∈-chloronorleucine. A relatively stable intermolecular cross-link was isolated and partially characterized by mass spectrometry as an aldol resulting from the reaction of the δ-semialdehyde derived from lysine and hydroxylysine.

Characterization of Chemical Impurities in Glutaraldehyde

1975 ◽  
Vol 33 ◽  
pp. 620-621
Author(s):  
B. J. Grenon ◽  
A. J. Tousimis
Keyword(s):  
Glutaric Acid ◽  
Spectroscopic Analysis ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Amorphous Solid ◽  
Water Soluble ◽  
Impurity Component ◽  
Chemical Impurities ◽  
Soluble Liquid

Ever since the introduction of glutaraldehyde as a fixative in electron microscopy of biological specimens, the identification of impurities and consequently their effects on biologic ultrastructure have been under investigation. Several reports postulate that the impurities of glutaraldehyde, used as a fixative, are glutaric acid, glutaraldehyde polymer, acrolein and glutaraldoxime.Analysis of commercially available biological or technical grade glutaraldehyde revealed two major impurity components, none of which has been reported. The first compound is a colorless, water-soluble liquid with a boiling point of 42°C at 16 mm. Utilizing Nuclear Magnetic Resonance (NMR) spectroscopic analysis, this compound has been identified to be — dihydro-2-ethoxy 2H-pyran. This impurity component of the glutaraldehyde biological or technical grades has an UV absorption peak at 235nm. The second compound is a white amorphous solid which is insoluble in water and has a melting point of 80-82°C. Initial chemical analysis indicates that this compound is an aldol condensation product(s) of glutaraldehyde.

scholarly journals Cross-linking modifications of HDL apoproteins by oxidized phospholipids: structural characterization, in vivo detection, and functional implications

2020 ◽  
Vol 295 (7) ◽  
pp. 1973-1984
Author(s):  
Detao Gao ◽  
Mohammad Z. Ashraf ◽  
Lifang Zhang ◽  
Niladri Kar ◽  
Tatiana V. Byzova ◽  
...  
Keyword(s):  
Density Lipoprotein ◽  
Cross Linking ◽  
Oxidized Phospholipids ◽  
Cross Link ◽  
In Vivo Detection ◽  
Lysine Residues ◽  
Cross Links ◽  
Human Atheroma

Apolipoprotein A-I (apoA-I) is cross-linked and dysfunctional in human atheroma. Although multiple mechanisms of apoA-I cross-linking have been demonstrated in vitro, the in vivo mechanisms of cross-linking are not well-established. We have recently demonstrated the highly selective and efficient modification of high-density lipoprotein (HDL) apoproteins by endogenous oxidized phospholipids (oxPLs), including γ-ketoalkenal phospholipids. In the current study, we report that γ-ketoalkenal phospholipids effectively cross-link apoproteins in HDL. We further demonstrate that cross-linking impairs the cholesterol efflux mediated by apoA-I or HDL3 in vitro and in vivo. Using LC-MS/MS analysis, we analyzed the pattern of apoprotein cross-linking in isolated human HDL either by synthetic γ-ketoalkenal phospholipids or by oxPLs generated during HDL oxidation in plasma by the physiologically relevant MPO-H2O2-NO2− system. We found that five histidine residues in helices 5–8 of apoA-I are preferably cross-linked by oxPLs, forming stable pyrrole adducts with lysine residues in the helices 3–4 of another apoA-I or in the central domain of apoA-II. We also identified cross-links of apoA-I and apoA-II with two minor HDL apoproteins, apoA-IV and apoE. We detected a similar pattern of apoprotein cross-linking in oxidized murine HDL. We further detected oxPL cross-link adducts of HDL apoproteins in plasma and aorta of hyperlipidemic LDLR−/− mice, including cross-link adducts of apoA-I His-165–apoA-I Lys-93, apoA-I His-154–apoA-I Lys-105, apoA-I His-154–apoA-IV Lys-149, and apoA-II Lys-30–apoE His-227. These findings suggest an important mechanism that contributes to the loss of HDL's atheroprotective function in vivo.

scholarly journals A new glycation product ‘norpronyl-lysine,’ and direct characterization of cross linking and other glycation adducts: NMR of model compounds and collagen

2014 ◽  
Vol 34 (2) ◽  
Author(s):  
Peter T. B. Bullock ◽  
David G. Reid ◽  
W. Ying Chow ◽  
Wendy P. W. Lau ◽  
Melinda J. Duer
Keyword(s):  
Model Systems ◽  
Cross Linking ◽  
Advanced Glycation ◽  
Model Compounds ◽  
Product Characterization ◽  
Glycation Product ◽  
Cross Links

NMR reveals numerous early and advanced glycation products, including a newly recognized ‘norpronyl-lysine,’ and cross links in solution, intact collagen and model systems. Solid state methods are directly applicable to in vitro and in vivo glycation pathway and product characterization.

scholarly journals Biosynthetic pathway of desmosines in elastin

1973 ◽  
Vol 136 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Gillian Francis ◽  
Rhys John ◽  
John Thomas
Keyword(s):  
Amino Acid ◽  
Biosynthetic Pathway ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Amino Acid Compositions ◽  
Lysine Residues ◽  
Cross Links

1. Elastins purified by various methods from the ligamentum nuchae and the lungs of cattle of various ages were analysed for amino acid compositions and lysine-derived cross-links. 2. In fully mature elastins from adults the main cross-links were desmosine, isodesmosine and lysinonorleucine and the so-called aldol-condensation product. Trace amounts of merodesmosine were also found. 3. During the normal maturation of elastins the amounts of desmosine, isodesmosine and lysinonorleucine increased, whereas the aldol-condensation product and intact lysine residues decreased and merodesmosine remained the same. 4. Elastins from young animals contained significant amounts of dehydromerodesmosine whereas elastins from adults contained virtually nil. Evidence is presented which suggests that the biosynthetic pathway of desmosine and isodesmosine proceeds via the aldol-condensation product and dehydromerodesmosine.

scholarly journals The borohydride-reducible compounds of human aortic elastin. Demonstration of a new cyclic amino acid in alkali hydrolysate, and changes with age and in patients with annulo-aortic ectasia including one with Marfan syndrome

1985 ◽  
Vol 232 (1) ◽  
pp. 169-175 ◽  
Author(s):  
T Halme ◽  
M Jutila ◽  
T Vihersaari ◽  
P Oksman ◽  
N D Light ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Marfan Syndrome ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Hydrolysis Product ◽  
Exchange Chromatography ◽  
Spectrometric Analysis ◽  
Cross Link ◽  
Aortic Ectasia ◽  
And Control

Human aortic elastin reduced with [3H]borohydride was analysed by ion-exchange chromatography after alkali or acid hydrolysis. Alkali hydrolysates of elastins contained a radioactive peak that was eluted between proline and leucine. This peak was not present in foetal elastin, but its proportion increased steadily during aging. Aortic samples from patients with annulo-aortic ectasia (aneurysm of the ascending aorta), including one with classical Marfan syndrome, contained less elastin (CNBr-insoluble material) than did the age-matched controls. The proportion of radioactivity in the new peak of all these aortas was low when compared with age-matched controls. Gas-chromatographic/mass-spectrometric analysis suggested that it contained a cyclic derivative of a hydrated aldol-condensation product. The concentration of the cross-link precursors, lysine aldehyde and aldol-condensation product (estimated from the acid-hydrolysis product 6-chloronorleucine and the acid-degradation product of reduced aldol-condensation product) was high in very young aortas but remained quite stable after childhood. No differences were observed in cross-link profiles of acid hydrolysates between pathological and control aortas. A low proportion of radioactivity in the new peak may indicate the presence of young or immature elastin in the pathological aortas.

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