Editing Coordination complex (section)

===Bioinorganic chemistry===
In [[bioinorganic chemistry]] and [[bioorganometallic chemistry]], coordination complexes serve either structural or catalytic functions. An estimated 30% of proteins contain metal ions.  Examples include the intensely colored [[Vitamin B12|vitamin B<sub>12</sub>]], the [[Heme|heme group]] in [[hemoglobin]], the [[cytochrome]]s, the [[Chlorin|chlorin group]] in [[chlorophyll]], and [[carboxypeptidase]], a hydrolytic enzyme important in digestion. Another complex ion enzyme is [[catalase]], which decomposes the cell's waste [[hydrogen peroxide]]. Synthetic coordination compounds are also used to bind to proteins and especially nucleic acids (e.g. anticancer drug [[cisplatin]]).