In biology, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site).
Seattle is rolling out 11 rainbow crosswalks in Capitol Hill this week, adding a colorful bang to the annual Pride celebration. The crosswalks cost the city $66,000, said Seattle Department of Transportation spokesman Rick Sheridan, and are permanent.
The cost of a regular crosswalk is about $1,000 or $4,000 per intersection. To replace 53 crosswalks will cost over half a million dollars. Too embark on a city-wide effort will cost quite a bit more.