Development of tyrosine aminotransferase and para-hydroxyphenylpyruvate dioxygenase activities in fetal and neonatal human liver.
نویسندگان
چکیده
In livers of fetuses of 220--340 g body wt, total cytosolic tyrosine aminotransferase activity was 1.0 nmol of product/mg of protein per min, and the corresponding values for autopsy livers of newborns of 740--1,475 g and 2,600--3,650 g were 1.5 and 5.7, respectively, as compared with the adult value of 12.7. On the other hand, para-hydroxyphenylpyruvate dioxygenase activity is at adult level already in fetuses less than 340 g body wt. The Km value for tyrosine of tyrosine aminotransferase (1 mM) was considerably higher than the corresponding value for para-hydroxyphenylpyruvate of para-hydroxyphenylpyruvate dioxygenase (50 micro M). These results suggest that tyrosine aminotransferase is the rate limiting enzyme in the catabolism of tyrosine in premature infants.
منابع مشابه
Certain aspects of tyrosine metabolism in the young. I. The development of the tyrosine oxidizing system in human liver.
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ورودعنوان ژورنال:
- The Journal of clinical investigation
دوره 70 1 شماره
صفحات -
تاریخ انتشار 1982