Crosslinking photo-activated

Andreev OA, Reshetnyak Y, Goldfarb RH. Evidence of inter- and intra-molecular crosslinking of tyrosine residues of carmodulin induced by photo-activation of ruthenium(II). Photochem Photobiol Sci 2002 1 834-6. 

The UV cure system contains an epoxy or a vinyl ether functionalized PDMS polymer and a photo catalyst [36]. This latter, a diaryliodonium salt is photolyti-cally decomposed to form an active acid that polymerizes the epoxy or vinyl ether groups and crosslinks the network. 

A brief investigation of the potential thermal and photo-lytical chemistry of resins 3 and 5 was undertaken. It was prompted by a report of the observation of site-site isolation on irradiation of 18% cross linked 3 (22). This is in contrast to soluble CpCo(C0)2 which forms di- and trinuc.lear clusters under the same conditions ( 33, 34). Similar apparent prevention of the formation of higher nuclear species was noted in the decarbonyla-tions of CH2Fe(C0)2H (22) and CH2Cgi(C0) 3H (M = Cr, Mo, W) (35), and in the catalytic activity of CfoCpTiCp (25). However, these species are all supported by a relativelyTiLghly cross linked polymer, and there was ample indication that lesser crosslinking enables "bimolecular" reactions of active centers (36,37,38,39). 

High activity of uranyl acetate as crosslinking sensitizer should be noted. Possibly, this may be explained from different points of view uranyl acetate belongs to the compounds that yield easily to photo-cemical excitation, and also uranyl acetate as radioactive compound may produce itself free radicals in neighboring polyester molecules. 

Figure 2.12 DNA crosslinking. The deleterious properties of nitrogen mustards are explained through the illustrated interstrand linkage mechanism that makes DNA impossible to duplicate or transcribe. Intrastrand crosslinking is the basis of action for anti-cancer drugs such as c/s-platin and carbo-platin. This is intended to prevent DNA duplication and hence cancer cell division. DNA crosslinking to proteins (such as histones) uses a non-covalent DNA intercalator with two azide functional groups. Both azides are activated for covalent coupling under photo-chemical conditions so that DNA subsequently becomes covalently linked to protein.

F. 10 Schematic representation for the photo-affinity-based ABPP strategy. The structure of HDAC photo-crosslinking probe (SAHA-BPyne) is shown in the middle [115]. ABPP activity-based protein profiling, HDAC histone deacetylase, SAHA suberoylanilide hydroxamic acid, CuAAC copper(l)-catalyzed azide-alkyne cycloaddition, LC-MS/MS liquid chromatography-tandem mass spectrometry... 

---