Enzymes
Proteins that act as a catalysts in mediating and speeding a specific chemical reaction. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosemia, an error in the handling (metabolism) of the sugar galactose.
Medical dictionary.
2011.