by drawing the structure in the usual way. Valence electrons in elements either exist as bonding pairs or lone pairs.īonding pairs are represented by a connecting line between atoms in a structure, i.e. Only P needs an expanded octet, but presents little problem since P only ever occurs as phosphate ester. Representing biochemical substances as Lewis structures is staightforward since the elements C, N, O and S form simple octets. The passage through the reaction space is like a mountain pass, with the transition state as a high point relative to reactant and product, but still stable relative to the "mountains" of wildly improbable structures on either side.
The reaction pathway should be plotted in multidimensional space rather than the usual 2-D graph. to be self consistent as Lewis structures.
Transition states and intermediates are less stable than reactants and products, but still need to follow normal chemical rules, e.g. Mechanistic basis of biochemical reactionsĪ chemical bond can be represented as an electron pair shared between two atoms:Ĭhemical reaction is the process of bond breaking, electron redistribution and bond formation giving rise to new structures.īetween initial reactant and final product, reactions may pass through transition states and intermediates. Mathews and Stryer do not include a general introduction to chemical mechanism. Schematic view of the enzyme citrate synthase,ĭepartment of Chemistry and Biochemistry Home PageĬhemical mechanisms in biochemical reactions. Department of Chemistry and Biochemistry - Chem*4520 Metabolic ProcessesĬhem*4520 Metabolic Processes Fall Semester 2000