Helix-Constrained Peptides Constructed by Head-to-Side Chain Cross-Linking Strategies

Unsaturated polyester was prepared with adipic acid (AA), fumaric acid (FA), itaconic acid (IA) and 1, 6-hexanediol (HD) by enzyme-catalyzed polmerization. The insoluble gel fraction (Qs), as the cross-linking degree of cured unsaturated polyesters which could be self-cross-linked at high temperature through C=C in it, was got by Soxhlet Extraction. The properties were investigated by FT-IR, 1H NMR, DSC, XRD and so on. The results indicated that the C=C in unsaturated diacids reduced the acitvity of N435, which affected the polmerization. With the introduction of C=C of IA or FA, the Mn of polyester reduced. The C=C could self-cross-link under high temperature for lengthy time. The higher the temperature and the longer the time, the Qs increased. As the C=C of IA was in the side chain, it could move easily. Then Qs of poly (AA-co-IA-co-HD) was higher than ploy (AA-co-FA-co-HD). With the increased content of unsaturated diacid, Qs increased. And the biodegradation of cross-linked polyesters became worse.

Download Full-text

Cross-Linking Behavior of Diskotic Side-Chain Polymers in Solution

Macromolecules ◽

10.1021/ma0354804 ◽

2004 ◽

Vol 37 (20) ◽

pp. 7839-7845 ◽

Cited By ~ 5

Author(s):

Marcel W. C. P. Franse ◽

Klaas te Nijenhuis ◽

Jan Groenewold ◽

Stephen J. Picken

Keyword(s):

Side Chain ◽

Cross Linking

Download Full-text

Preparation of polyferrocenylsilane via thermal ROP, synthesis of polyferrocenylsilane with methacrylate side chain and its photochemical cross-linking properties

Materials Letters ◽

10.1016/j.matlet.2005.11.055 ◽

2006 ◽

Vol 60 (11) ◽

pp. 1416-1419 ◽

Cited By ~ 8

Author(s):

Jian-Jun Wang ◽

Li Wang ◽

Xue-Jie Wang ◽

Tao Chen ◽

Hao-Jie Yu ◽

...

Keyword(s):

Side Chain ◽

Cross Linking

Download Full-text

Engineering oxidative stability in human hemoglobin based on the Hb providence (βK82D) mutation and genetic cross-linking

Biochemical Journal ◽

10.1042/bcj20170491 ◽

2017 ◽

Vol 474 (24) ◽

pp. 4171-4192 ◽

Cited By ~ 7

Author(s):

Michael Brad Strader ◽

Rachel Bangle ◽

Claire J. Parker Siburt ◽

Cornelius L. Varnado ◽

Jayashree Soman ◽

...

Keyword(s):

Oxidative Degradation ◽

Oxygen Affinity ◽

Side Chain ◽

Cross Linking ◽

Critical Element ◽

Low Oxygen ◽

Naturally Occurring ◽

Low Concentrations ◽

Genetic Cross ◽

Low Oxygen Affinity

Previous work suggested that hemoglobin (Hb) tetramer formation slows autoxidation and hemin loss and that the naturally occurring mutant, Hb Providence (HbProv; βK82D), is much more resistant to degradation by H2O2. We have examined systematically the effects of genetic cross-linking of Hb tetramers with and without the HbProv mutation on autoxidation, hemin loss, and reactions with H2O2, using native HbA and various wild-type recombinant Hbs as controls. Genetically cross-linked Hb Presbyterian (βN108K) was also examined as an example of a low oxygen affinity tetramer. Our conclusions are: (a) at low concentrations, all the cross-linked tetramers show smaller rates of autoxidation and hemin loss than HbA, which can dissociate into much less stable dimers and (b) the HbProv βK82D mutation confers more resistance to degradation by H2O2, by markedly inhibiting oxidation of the β93 cysteine side chain, particularly in cross-linked tetramers and even in the presence of the destabilizing Hb Presbyterian mutation. These results show that cross-linking and the βK82D mutation do enhance the resistance of Hb to oxidative degradation, a critical element in the design of a safe and effective oxygen therapeutic.

Download Full-text

Oxidative Chemistry in the GFP Active Site Leads to Covalent Cross-Linking of a Modified Leucine Side Chain with a Histidine Imidazole: Implications for the Mechanism of Chromophore Formation†,‡

Biochemistry ◽

10.1021/bi0503798 ◽

2005 ◽

Vol 44 (23) ◽

pp. 8303-8311 ◽

Cited By ~ 18

Author(s):

Matthew A. Rosenow ◽

Hetal N. Patel ◽

Rebekka M. Wachter

Keyword(s):

Active Site ◽

Side Chain ◽

Cross Linking

Download Full-text

Tyrosine Metabolism in Blowfly Larvae at Pupation

Australian Journal of Biological Sciences ◽

10.1071/bi9640803 ◽

1964 ◽

Vol 17 (3) ◽

pp. 803 ◽

Cited By ~ 5

Author(s):

RH Hackman KN Saxen

Keyword(s):

Direct Evidence ◽

Side Chain ◽

Cross Linking ◽

Cuticular Protein ◽

Oxidative Deamination ◽

Tyrosine Metabolism ◽

Metabolic Reactions

In insects tyrosine has been regarded as participating in metabolic reactions which lead, not only to its incorporation in various proteins, but also to sclerotization of the cuticle (i.e. quinone cross-linking of cuticular protein). Three different meta-bolic pathways have been suggested, all of which lack direct evidence to support them. The suggested pathways are (i) oxidative deamination leading to the formation of o-quinones, (ii) non-specific hydroxylation and elimination of the side-chain leading to the formation of p-quinones, and (iii) conversion to N-acetyldopamine which is the phenolic precursor of the sclerotizing quinone. For a review of these theories see Pryor (1962) and Hackman (1964).

Download Full-text