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- *****************************************************************
- * Aminotransferases class-I pyridoxal-phosphate attachment site *
- *****************************************************************
-
- Aminotransferases share certain mechanistic features with other pyridoxal-
- phosphate dependent enzymes, such as the covalent binding of the pyridoxal-
- phosphate group to a lysine residue. On the basis of sequence similarity,
- these various enzymes can be grouped [1,2] into subfamilies. One of these,
- called class-I, currently consists of the following enzymes:
-
- - Aspartate aminotransferase (AAT) (EC 2.6.1.1). AAT catalyzes the reversible
- transfer of the amino group from L-aspartate to 2-oxoglutarate to form
- oxaloacetate and L-glutamate. In eukaryotes, there are two AAT isozymes:
- one is located in the mitochondrial matrix, the second is cytoplasmic. In
- prokaryotes, only one form of AAT is found (gene aspC).
- - Tyrosine aminotransferase (EC 2.6.1.5) which catalyzes the first step in
- tyrosine catabolism by reversibly transferring its amino group to 2-
- oxoglutarate to form 4-hydroxyphenylpyruvate and L-glutamate.
- - Aromatic aminotransferase (EC 2.6.1.57) involved in the synthesis of Phe,
- Tyr, Asp and Leu (gene tyrB).
- - 1-aminocyclopropane-1-carboxylate synthase (EC 4.4.1.14) (ACC synthase)
- from plants. ACC synthase catalyzes the first step in ethylene
- biosynthesis.
-
- The sequence around the pyridoxal-phosphate attachment site of this class of
- enzyme is sufficiently conserved to allow the creation of a specific pattern.
-
- -Consensus pattern: [GS]-[LIVMFYTC]-[SA]-K-x(2)-[GSALV]-[LIVMF]-x-[GNAR]-x-R-
- [LIVMA]-G
- [K is the pyridoxal-P attachment site]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
- -Last update: June 1994 / Pattern and text revised.
-
- [ 1] Bairoch A.
- Unpublished observations (1992).
- [ 2] Sung M.H., Tanizawa K., Tanaka H., Kuramitsu S., Kagamiyama H.,
- Hirotsu K., Okamoto A., Higuchi T., Soda K.
- J. Biol. Chem. 266:2567-2572(1991).
-