Enzyme

Description

A unique class of componds that originate in living cells and are capable of catalyzing specific chemical reactions in other organic compounds. More than 1000 enzymes have been identified. Most are proteins, but a few newly discovered ones are ribonucleic acids. Enzymes are classified by the types of reactions they catalyze:

1) Hydrolases (proteolytic enzymes) accelerate reactions with water,

2) Oxidoreductases regulate oxidation and reduction reactions usually by acting as an oxygen acceptor or donor,

3) Transferases aid in the transferring of specific functional groups,

4) Lyases remove or add specific functional groups,

5) Ligases combine one or more molecules and

6) Isomerases can racemize compounds.

Enzymes have long been used for fermentation and more recently have been used to remove stains and to breakdown and solubilize otherwise insoluble materials.

Synonyms and Related Terms

biocatalyst

Examples: amylase, carboxylase, cellulase, cholinesterase, chymotrypsin, invertase, lipase , maltase, pepsin, protease, rennin, ribonuclease, trypsin, urease, zymase

Additional Information

R. Wolbers, N. Sterman and C. Stavroudis, "Notes for Workshop on New Methods in the Cleaning of Paintings", 1990, GCI, Los Angeles.

Sources Checked for Data in Record

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Encyclopedia Britannica, http://www.britannica.com Comment: "enzyme" Encyclopædia Britannica [Accessed January 28, 2002].

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• Rosalie Rosso King, Textile Identification, Conservation, and Preservation, Noyes Publications, Park Ridge, NJ, 1985

• Richard C. Wolbers, Nanette T. Sterman, Chris Stavroudis, Notes for Workshop on New Methods in the Cleaning of Paintings, J.Paul Getty Trust, Los Angeles, 1990

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000