Substrates in biological cells must be continuously transported ... which together form a complex three-dimensional structure ...

This is the first experimental structure of a productive proteinase–cofactor–macromolecular substrate complex. Furthermore, it provides a template for the design of improved plasminogen ...

Enzymes are biological catalysts that speed up chemical reactions in living organisms ... The active site of an enzyme has a unique three-dimensional structure that allows it to bind to a specific ...

It is a perfect match to the shape of the substrate molecule ... and therefore the enzyme has a unique shape. This structure is held together by weak forces between the amino acid molecules ...