Biological implication

Many publications on cation-sugar complexes refer, in their introduction, to the great biological importance of this subject In fact, however, there is very little evidence for the involvement of complexes of neutral carbohydrates in biological systems, in contrast to the complexes of acidic carbohydrates. 

The nature of complex-formation between cations and monosaccharides is now well understood this knowledge should form a firm basis for the study of cation-polysaccharide interactions. 

The Anomeric and Exo-anomeric Effects in Potential-Function Calculations. .. 103 

The concepts of conformational analysis are fimdamental to a proper understanding of the relationship between the structure and properties of carbohydrates. The general application of conformational analysis has been stimulated by the relative universality of its fundamental postulates, especially on the qualitative level. The leading notion is the quantification of 

Copyright e 1989 by Academic Pmsa, loc. All rights of Fefwoduction in any form resMYed. 

The first determination of an experimental heat of combustion of a strained amide or lactam, that of methylpenidllin (5), was reported by R.B. Woodward and NBS collaborators in 1949 [18], It indicated a strain energy in the 4-membered ring some 6 kcal/mol higher than in the model monocyclic feta-lactams (6). This added strain is, in part, responsible for the biological activity of the penicillins. Over twenty years later, Sweet and Dahl used X-ray data to correlate increased lactam distortion in feto-lactam antibiotics with enhanced biological activities [19]. 

In the realm of protein chemistry, Ramachandran [20] emphasized the need to abandon the assumption of absolute planarity in peptide linkages. It is recognized that binding with an enzyme strains and activates substrates [21], For peptidases and proteases this involves distortion of the scissile peptide (amide) linkage and specific distortions may lead to specific stereochemical consequences [22], 

Our fully-optimized 6-31G ab initio molecular orbital calculations support a strong preference for N-protonation of 3 while indicating that N- and O-protonation are competitive in 1-azabicyclo-[3.3. l]nonan-2-one (11) [35-37]. More recent results on other systems will be described. 

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There are, indeed, many biological implications that have been triggered by the advent of fullerenes. They range from potential inhibition of HIV-1 protease, synthesis of dmgs for photodynamic therapy and free radical scavenging (antioxidants), to participation in photo-induced DNA scission processes [156, 157, 158, 159, 160, 161, 162 and 163]. These examples unequivocally demonstrate the particular importance of water-soluble fullerenes and are summarized in a few excellent reviews [141, 1751. 

Foresti R, Shurey C, Ansari T et al (2005) Reviewing the use of carbon monoxide-releasing molecules (CO-RMs) in biology implications in endotoxin-mediated vascular dysfunction. Cell Mol Biol (Noisy-le-grand) 51 409-423... 

Polynuclear complexes of iron and their biological implications. T. G. Spiro and P. Saltman, Struct. Bonding (Berlin), 1969, 6, 116-156 (170). 

Aspects of Organo-Transition-Metal Photochemistry and Their Biological Implications... 

Spiro G, Saltman P (1969) Polynuclear Complexes of Iron and Their Biological Implications. 6 116-156... 

Such a result may have interesting biological implications, for it represents one-electron transfer processes in discrete stages, which is presumably the way oxidation-reduction reactions occur in nature. 

The basic mechanisms of lipid peroxidation are well understood and described in the literature in many excellent reviews (e.g. Girotti, 1985 Gardner, 1989 Buettner, 1993). Here, apart from essential background information, we will restrict our discussion in this short overview to recent advances in our understanding of lipid peroxidation, emphasizing those aspects relevant to coronary heart disease. Some of the biological implications of these reactions will be discussed by others in this volume. 

Spiro, G., Saltman, P. Polynuclear Complexes of Iron and their Biological Implications. Vol. 6, pp. 116-156. 

The chemical and biological implications of compounds that support reversible but covalent processes are often lost in a common assumption that all covalent reactions of DNA are irreversible. Difficulty with reversible reactions is often encountered while attempting to isolate labile products as mentioned above and described more fully in Section 9.2. Yet, reversibility also has the potential to extend the effective lifetime of transient intermediates (Section 9.3.2) and support selective, target-promoted QM... 

Riesz P, Kondo T (1992) Free radical formation induced by ultrasound and its biological implications. Free Radic Biol Med 13 247-270... 

The photodimerization of pyrimidine bases continues to attract attention, undoubtedly because of the biological implications of such transformations. 1,3-Dimethyluracil affords four [ 2 + 2] dimers on irradiation in an ice-matrix.192 Analogous dimeric species have been obtained under a variety of conditions from dimethylthymine,193 tetramethyluracil,194 5-methyloro-... 

Apart from the biological implications, aspects of the chemistry of macrocyclic ligands are of relevance to a diverse number of other areas. Indeed, there has been a remarkable expansion of research involving these other areas during recent times. Many of the developments impinge on topics such as metal-ion catalysis, organic synthesis, metal-ion discrimination, and analytical methods, as well as on a number of potential industrial, medical and other applications. 

He is the author of Superoxide Ion Chemistry and Biological Implications (Volumes 1 and 2, CRC Press, 1989 1990) and the co-author of several jointed books on free radicals. He has published about 100 works. 

IB Afanas ev. Superoxide Ion Chemistry and Biological Implications, vol 2. Boca Raton, FL CRC Press, 1990. 

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