Search results
Results from the WOW.Com Content Network
Type II tyrosinemia is caused by a deficiency of the enzyme tyrosine aminotransferase (EC 2.6.1.5), encoded by the gene TAT.Tyrosine aminotransferase is the first in a series of five enzymes that converts tyrosine to smaller molecules, which are excreted by the kidneys or used in reactions that produce energy.
In humans, the tyrosine aminotransferase protein is encoded by the TAT gene. [7] A deficiency of the enzyme in humans can result in what is known as type II tyrosinemia, wherein there is an abundance of tyrosine as a result of tyrosine failing to undergo an aminotransferase reaction to form 4-hydroxyphenylpyruvate. [8]
It is a 4-hydroxyphenylpyruvate dioxygenase inhibitor indicated for the treatment of hereditary tyrosinemia type 1 (HT-1) in combination with dietary restriction of tyrosine and phenylalanine. [7] Liver transplant is indicated for patients with tyrosinemia type I who do not respond to nitisinone, as well as those with acute liver failure and ...
HPPD is an enzyme that usually bonds to form tetramers in bacteria and dimers in eukaryotes and has a subunit mass of 40-50 kDa. [7] [8] [9] Dividing the enzyme into the N-terminus and C-terminus one will notice that the N-terminus varies in composition while the C-terminus remains relatively constant [10] (the C-terminus in plants does differ slightly from the C-terminus in other beings).
The systematic name of this enzyme class is 3,5-diiodo-L-tyrosine:2-oxoglutarate aminotransferase. Other names in common use include diiodotyrosine aminotransferase , halogenated tyrosine aminotransferase , and halogenated tyrosine transaminase .
The aromatic side chain of phenylalanine is hydroxylated by the enzyme phenylalanine hydroxylase to form tyrosine. The conversion from tyrosine to 4-HPPA is in turn catalyzed by tyrosine aminotransferase. [2] Additionally, 4-HPPA can be converted to homogentisic acid which is one of the precursors to ochronotic pigment. [3]
The primary treatment for type 1 tyrosinemia is nitisinone and restriction of tyrosine in the diet. [6] Nitisinone inhibits the conversion of 4-OH phenylpyruvate to homogentisic acid by 4-Hydroxyphenylpyruvate dioxygenase, the second step in tyrosine degradation. By inhibiting this enzyme, the accumulation of the fumarylacetoacetate is ...
Phenylalanine hydroxylase (PAH) (EC 1.14.16.1) is an enzyme that catalyzes the hydroxylation of the aromatic side-chain of phenylalanine to generate tyrosine.PAH is one of three members of the biopterin-dependent aromatic amino acid hydroxylases, a class of monooxygenase that uses tetrahydrobiopterin (BH 4, a pteridine cofactor) and a non-heme iron for catalysis.