Metabolic studies in a patient with hepatic cytosol tyrosine aminotransferase deficiency

ABSTRACT _Extract_: Metabolic studies on a patient having multiple congenital anomalies and defective hepatic soluble tyrosine aminotransferase activity are presented. The activities of

hepatic mitochondrial tyrosine aminotransferase and soluble _p_-hydroxyphenylpyryvate hydroxylase were normal. When untreated, levels of tyrosine in plasma rose as high as 62 mg/100 ml. He

had phenolic aciduri (3.1–4.9 mg/mg creatinine) with _p_-hydroxyphenylpyruvic acid (0.6-1.8 mg/mg creatinine), _p_-hydroxyphenylacetic acid (0.7–1.2 mg/mg creatinine),

_p_-hydroxyphenyllactic acid (1.0–1.7 mg/mg creatinine), and _N_-acetyltyrosine (0.9–1.6 mg/mg creatinine). These metabolites were identified by gas chromatography-mass spectrometry.

Excretion of _p_-tyramine was grossly elevated (17–44 _μg_/mg creatinine) and was not reduced by orally administered antibiotics. Oral tolerance tests showed rapid conversion of

phenylpyruvic acid to phenylalanine and of phenylalanine to tyrosine. _Speculation_: The results described suggest the need to reexamine subcellular distribution of enzymes both in normal

subkects and in patients with inborn errors of metabolism. When methods are developed to fractionate tyrosine aminotransferase, it may become apparent that there are several isozymes under

individual genetic control. Accumulation of an intermediary metabolite should not be taken as conclusive evidence of a primary abnormality of its catabolism. The similarity of the findings

in the urine of a patient with hepatic soluble tyrosine aminotransferase deficiency and in tyrosyluric neonates suggests that delayed maturation of soluble tyrosine aminotransferase rather

than _p_-hydroxyphenylpyruvate hydroxylase might be present in at least some of these infants. SIMILAR CONTENT BEING VIEWED BY OTHERS PHENYLKETONURIA Article 20 May 2021 A RECURRENT DE NOVO

ATP5F1A SUBSTITUTION ASSOCIATED WITH NEONATAL COMPLEX V DEFICIENCY Article 06 September 2021 DETERMINANTS OF TYROSINAEMIA DURING NITISINONE THERAPY IN ALKAPTONURIA Article Open access 27

September 2022 ARTICLE PDF AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Division of Genetics and Department of Pediatrics, University of Oregon Medical School, Portland, Oregon, USA Nancy G

Kennaway & Neil R M Buist Authors * Nancy G Kennaway View author publications You can also search for this author inPubMed Google Scholar * Neil R M Buist View author publications You

can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Kennaway, N., Buist, N. Metabolic Studies in a

Patient with Hepatic Cytosol Tyrosine Aminotransferase Deficiency. _Pediatr Res_ 5, 287–297 (1971). https://doi.org/10.1203/00006450-197107000-00002 Download citation * Issue Date: 01 July

1971 * DOI: https://doi.org/10.1203/00006450-197107000-00002 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a

shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative KEYWORDS * mental retardation * phenolic

acids * tyrosine aminotransferase deficency * tyrosinemia * tyrosyluria