Enzyme active sites steric forces

Enzyme active sites, 136,148, 225. See also Protein active sites in carbonic anhydrase, 197-199 in chymotrypsin, 173 in lysozyme, 153, 157 nonpolar (hypothetical site), 211-214 SNase, 189-190,190 steric forces in, 155-158, 209-211, 225 in subtilisin, 173 viewed as super solvents, 227 Enzyme cofactors calcium ... 

The reason for this must come from the way in which the substrate interacts with the osmium-ligand complex. However, the detailed mechanism of the asymmetric dihydroxylation is stUl far from clear-cut. What is known is that the ligand forms some sort of chiral pocket, like an enzyme active site, with the osmium sitting at the bottom of it. Alkenes can only approach the osmium if they are correctly aligned in the chiral pocket, and steric hindrance forces the alignment shown in the scheme above. The analogy with an enzyme active... 

The conformational distortions that attend transition state formation involve both steric and electronic changes to the active site structure of the enzyme. These changes can include changes in steric packing forces, van der Waals interactions,... 

A substrate binds an enzyme at the active site. Substrate-enzyme binding is based on weak intermolecular attractions contact forces, dipole forces, and hydrogen bonding. Steric effects also play an important role because the substrate must physically fit into the active site. Some enzymes have confined active sites, while others are open and accessible. A restricted active site can lead to high selectivity for a specific substrate. Low specificity can be advantageous for some enzymes, particularly metabolic and digestive enzymes that need to process a broad range of compounds with a variety of structures. Because enzymes are composed of chiral amino acids, enzymes interact differently with stereoisomers, whether diastereomers or enantiomers. 

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