Transaminase involved in tyrosine breakdown. Converts tyrosine to p-hydroxyphenylpyruvate. Can catalyze the reverse reaction, using glutamic acid, with 2-oxoglutarate as cosubstrate (in vitro). Has much lower affinity and transaminase activity towards phenylalanine. 2-oxoglutarate + L-tyrosine = 3-(4-hydroxyphenyl)pyruvate + L-glutamate Amino-acid degradation; L-phenylalanine degradation; acetoacetate and fumarate from L-phenylalanine: step 2/6. Homodimer. The disease is caused by variants affecting the gene represented in this entry. Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.