Catalysis, biochemical

Enzymes are complex nitrogeneous organic compounds. They are produced in die living cells of plants and animals. On dissolving in water they form the colloidal solution, hence they behave as very active catalysts in certain biochemical reactions and are known as biochemical catalysts and the phenomenon itself is known as biochemical catalysis. 

Vazquez-Duhalt R, Torres E, Valderrama B et al (2002) Will biochemical catalysis impact the petroleum refining industry Energy Fuels 16 1239-1250... 

Hopkins Biochemistry Problems of Specificity in Biochemical Catalysis 33rd Robert Boyle Lecture, 1931 (p. 223)... 

Within the c/x plot for bidentate complexation there is a very constrained region containing all the classical (and some exotic or nltratrace) essential metal ions other than Cn, which exert biocatalytic functions in the center. The heavier alkaline earths Ca. Sr (for corals and foraminifers) and Ba (in desmides) are essential elements bnt hardly for pnrposes of biochemical catalysis, that is, substrate binding measured by c and x does not matter for heavy alkaline earth essentiality. 

Palfey BA, Massey V. Flavin-dependent enzymes. In Comprehensive Biochemical Catalysis. Sinnott M, ed. 1998. Academic Press, New York, pp. 83-154. 

Natural waters are often in a highly dynamic state with regard to oxidation-reduction rather than in or near equilibrium. Most oxidation-reduction reactions have a tendency to be much slower than acid-base reactions, especially in the absence of suitable biochemical catalysis. Nonetheless, equilibrium diagrams can greatly aid attempts to understand the possible redox patterns in natural waters and in water technological systems. 

Proton transfer between donor and acceptor located on a surface of a protein, or a membrane, is a true representation of many reactions taking place in biochemical catalysis, and is the essence of proton-driven coupled reactions. The ability to measure and analyze the dynamics of proton flux between two defined sites allows one to probe a specific area of a macromolecule surface. 

The rates measured reflect directly the physical-chemical properties of the water molecule in the nearby hydration shell. These measurements can gauge the properties of the water in an active site where biochemical catalysis takes place. Insertion of proton emitter in a specific site can be useful to determine the internal geometry of a site in a soluble, functioning protein. The subnanosecond measurement is equivalent to a strobe light that freezes in time a transient conformation of a protein. 

A somewhat different but mechanistically related reaction is the [2 -f 3] cycloaddition of a functionalized alkyne or nitrile to an azide to form a disubstituted triazole (120) or tetrazole ring (121, 122), linking the respective functionalities irreversibly (Scheme 14b). This click chemistry was used by Sharpless and co-workers (120) in 2001 as a tool to probe biochemical catalysis and substrate activation. The ease of the Cu(I)-catalyzed reaction has created a true explosion (120-160) of simple coupling-functionalization chemistry of all types of biochemical components (sugars, DNA, proteins, enzymes, substrates, inhibitors) (131, 135, 136, 139, 142, 155, 157-160), polymers (126, 134, 140, 147, 154),... 

The second area is models for enzyme catalysis itself. Here, as a first approximation, one will deny the idea that only a macromolecule can have enzyme-like properties. It is an open question whether or not a macromolecule is required, but this paper indicates some of the approaches one can make to this type of thing. In other words, what can one do about a model for the enzyme part of biochemical catalysis ... 

This disproportion between cause and effect, as well as this immutability, which is found with all these active substances, justifies their being gathered into a well-characterized group. To this class of bodies has been given various names, such as soluble ferments, diastases, or better still, enzymes. A detailed study shows that all these substances offer a close analogy to the so-called catalysts of inorganic chemistry. It therefore appears to us that the term biochemical catalysis would be a most suitable... 

Much rarer are used redox-couples of anions like NO /NH, HCO / CH, SO "/HS , etc. Their equilibrium ratio is reached much slower. The reason is that these reactions have high activation energy associated with the destruction of strong covalent bonds. For this reason, many of them are implemented only on the accoimt of biochemical catalysis (for instance, NO " NOj ). Rates of such processes are very low and imstable as they depend on the environment, nature and abundance of microbial populations and sufficiency of substrate for them. Many redox reactions of these couples are essentially irreversible. Their half-life may reach several years. The only relatively rapid process is oxidation of sulphide sulphur in alkaline medium. Besides, concentrations of anions often depend on pH value. For this reason. Eh value of individual anion redox-couples rarely may be a criterion of the solutions oxidation potential as a whole. 

Fe VFe and Cu are involved in biochemical catalysis especially in electron transfer under physiological conditions. FeS-proteins are active in the redox reactions of mitochondria and chloroplasts. Fe-porphyrins as cytochromes... 

Figure 2.3 Structures of other pterins used in biochemical catalysis.

FIG. 4.5 Element concentrations in the ocean today. Elements are shaded according to their category and arranged according to their concentrations in modern ocean water. Arrows show if element concentrations have increased or decreased since life began. Note how the elements that maintain balance are high concentration, those that are used for building are medium concentration, and those that are used for biochemical catalysis are low concentration (but still present for life). 

Hopkins, F. G. (1931) Problems of Specificity in Biochemical Catalysis, Oxford Univ. Press, London. 16 Kluyver, a. j. (1931) The Chemical Activities of Microorganisms, p. 95, Univ. of London Press Ltd. 17. Kornbero, A. (1974) DNA Synthesis. W. H. Freeman, San Francisco. 

E. J. Corey, N. J. Cooper, and M. L. H. Green (1977), Biochemical catalysis involving coenzyme B12 A rational stepwise mechanistic interpretation of vicinal interchange rearrangements. Proc. Nat. Acad. Sci. USA 74, 811-815. 

Hopkins, F. G. (1931), The Problems of Specificity in Biochemical Catalysis. Oxford. 

Bioelectrocatalysis is a unique combination of electrochemical and biochemical reactions, which rests not only on the ability to control at will the oxidizing and reducing ability of the electrode by changing its Fermi level, but on the specificity and selectivity of biochemical catalysis. Endeavors have been made to develop bioelectrocatalysis with enzymes that catalyze redox reactions. 

Chemical and Biochemical Catalysis for Next Generation Biofuels 5 Molecular Solar Fuels... 

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