Cross-linkage, protein

Exposure of proteins to ROS can lead to the formation of protein-protein cross-linkages... 

Protein cross linkages are important in determining the chemical properties of these novel cofactors. In galactose oxidase, the covalent link between the cysteine and tyrosine helps lower the redox potential of the radical to a value consistent with its ready generation in vivo. In lysyl oxidase, however, the quinone derived from trihydroxyphenylalanine... 

It was shown previously that 8-MOP inhibits the DNA synthesis in the epidermal cells [190]. Angelicin (4) and 4,6,3 -TMA are unable to induce significant level of DNA-protein cross-link. Although the DNA-protein cross linkage may well be related to the phototoxic reaction of... 

Various oxidation and condensation products (R = OH, CONHR R = OH, NHR) were isolated from a heated, neutral solution. It can be assumed from the structures shown that protein cross-linkages are possible if, e. g., Ri and R2 represent the 8-amino group of lysine (Formula 4.83). 

Cross-linkage - bifunctional agents may form covalent bonds with each of two adjacent guanine residues and such inter-strand cross-links will lead to inhibition of DNA replication and transcription. Intra-strand and DNA-protein cross-links may also be formed ... 

In general, the mechanism of heat and alkaline solution for DNA extraction may be based upon a hypothesis, previously proposed for the AR technique.32 Strong alkaline solution may denature and hydrolyze proteins, resulting in breaking cell and nuclear membranes as well as disrupting cross-linkages due to formalin fixation. It is no surprise to observe the similarity between retrieval of nucleic acid and retrieval of protein (antigen) based on a similar chemical reaction of formaldehyde with these two kinds of macromolecules (Fig. 3.1).15"19... 

Wang, K., and Richards, F. (1974) An approach to nearest neighbor analysis of membrane proteins. Application to the human erythrocyte membrane of a method employing cleavable cross-linkages. J. Biol. Chem. 249, 8005-8018. 

Cross Linkages in Protein Chemistry Johan Bjorksten... 

Isocyanates mediate their toxicity through a high degree of chemical reactivity. These reactions can result in cross-linkages of biological macromolecules that lead to the denaturation of proteins, the loss of enzyme function, and the formation of immunologic reactivities. 

The chloroethyl moiety of these nitrosoureas is capable of alkylating nucleic acids and proteins and producing single-strand breaks and interstrand cross-linkage... 

In addition to interest in this enzyme because of its catalytic characteristics, a considerable body of information has accumulated on staphylococcal nuclease as a protein molecule. Its relatively small size, the absence of covalent cross-linkages, and its behavior upon binding a variety of ligands have made it an ideal model substance for the study of various aspects of protein chemistry including X-ray crystallography. These investigations are reviewed in the present chapter and in Chapter 7 by Cotton and Hazen, this volume, on the three-dimensional structure (19). 

Schiff base interactions between aldehydes and amines typically are not stable enough to form irreversible linkages. These bonds may be reduced with sodium cya-noborohydride or a number of other suitable reductants (Chapter 3, Section 4) to form permanent secondary amine bonds. However, proteins cross-linked by glutaraldehyde without reduction nevertheless show stabilities unexplainable by simple Schiff base... 

Hawkins RB (1978) Quantitative determination of cross-linkage of bacteriophage DNA and protein by ionizing radiation. Int J Radiat Biol 33 425-441... 

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