Enzymes link atoms

During in vivo studies under biologically relevant conditions, the cis-Pt loading of the DNA is much lower than for the above-mentioned in vitro studies. It has been calculated that mortality of HeLa cells occurs at an value of 10 5 (i.e., one bound cis-Pt molecule per 105 nucleotides) (64a). This excludes atomic absorption spectroscopy for identification of the in vivo adducts. Immunochemical techniques, however, have shown to be very promising, and high sensitivity and selectivity levels have been reached. At the moment, only a few studies in which antibodies are raised against cis-Pt-treated DNA (64) or against synthetic cis-Pt adducts with mono- or dinucleotides are available (64a). With the latter method, quantitation of the different platinum-DNA adducts formed under in vivo conditions is possible. At the moment, femtomole (10-15 mol) amounts of the adducts can be detected with competitive enzyme-linked immunosorbent assay (ELISA) techniques. It has been demonstrated in this manner that the GG-Pt adduct is also the predominant adduct under in vivo conditions. 

Atomic Absorption Spectrometry Acetylcholinesterase British Anti-Lewisite Carboxylesterase Central Nervous System Chemical Warfare Agent 2-chlorovinylarsonous Acid Enzyme-linked Immunosorbent Assay Environmental Protection Agency... 

For the majority of enzyme-catalysed reactions, covalently bonded parts of the system must be separated into QM and MM regions. There has been considerable research into methods for QM/MM partitioning of covalently bonded systems. Important methods include the local self-consistent field (LSCF) method,114115 and the generalized hybrid orbital (GHO) technique.116 Alternatively a QM atom (or QM pseudo-atom) can be added to allow a bond at the QM/MM frontier for example, the link atom method or the connection atom method. 

Specific enzymes link the oligosaccharide units on proteins either to the side-chain oxygen atom of a serine or threonine residue or to the side-chain amide nitrogen atom of an asparagine residue. Protein gly-cosylation takes place in the lumen of the endoplasmic reticulum. The. hi-linked oligosaccharides are synthesized on dolichol phosphate and subsequently transferred to the protein acceptor. Additional sugars are attached in the Golgi complex to form diverse patterns. 

The Use of Enzyme-Linked Immunosorbent Assay fELISAl and Atomic Absorbance Spectrometry fAAS for Determination of Cisplatin-DNA Adducts. 

The stmctural and conformational analysis of proteins adsorbed to solid surfaces is difficult because most common analytical methods are not compatible with the presence of the interacting solids. With recent developments in instrumentation and techniques, our understanding of protein adsorption behavior has improved considerably [4, 14]. The most commonly used techniques include attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), radiolabeling techniques, immunofluorescence enzyme-linked immunosorbent assay (ELISA), ellipsometry, circular dichroism (CD) spectroscopy, surface plasmon resonance (SPR), and amide HX with nuclear magnetic resonance (NMR). Atomic force microscopy (AFM) and scanning... 

Although iron is essential for normal functioning of the human body, it may aiso play a deleterious role as a trigger of various diseases [ 1,2]. In this chapter, we will present results of studies on the role of iron in neurodegenerative diseases such as Parkinson s disease (PD), Alzheimer s disease (AD), and progressive supranuclear palsy (PSP). We report on studies whose main tool was Mossbauer spectroscopy, but also other complementary techniques such as electron microscopy, enzyme-linked immunosorbent assay (ELISA), and atomic absorption. 

FIGURE 18.32 Biotin is covalently linked to a protein via the e-amino group of a lysine residue. The biotin ring is thus tethered to the protein by a 10-atom chain. It functions by carrying carboxyl groups between distant sites on biotin-dependent enzymes. 

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