Coufalik A, Monder C
Biol Neonate. 1978;34(3-4):161-6. doi: 10.1159/000241120.
The enzymes of the tyrosine oxidase (TO) system of rat liver were measured during pre- and postnatal development. At all ages, the rate of tyrosine oxidation was limited by the activity of tyrosine aminotransferase (TAT). TAT of liver was undetectable from 4 days to 1 day before birth and was lower than p-hydroxyphenylpyruvate oxidase (pHPPO) and homogentisate oxidase (HO) postnatally. At birth, TAT, pHPPO, and HO were 2.9, 13, and 40% of adult values, respectively. Relative levels in fetal liver were HO greater than pHPPO greater than TAT. When enzyme activities were adjusted to compensate for dilution by hematopoietic cells, absolute activities increased, but other relationships remained the same. pHPPO rose at 15-17 days after birth and exceeded adult values at 31 days. HO was unchanged after birth. We conclude that each enzyme of TO follows a unique developmental path, with no concerted control of the entire TO system.
在大鼠肝脏酪氨酸氧化酶（TO）系统的产前和产后发育过程中，对其酶进行了测定。在所有年龄段，酪氨酸氧化速率均受酪氨酸转氨酶（TAT）活性的限制。肝脏中的TAT在出生前4天到1天无法检测到，产后低于对羟基苯丙酮酸氧化酶（pHPPO）和尿黑酸氧化酶（HO）。出生时，TAT、pHPPO和HO分别为成年值的2.9%、13%和40%。胎儿肝脏中的相对水平为HO大于pHPPO大于TAT。当调整酶活性以补偿造血细胞的稀释时，绝对活性增加，但其他关系保持不变。pHPPO在出生后15 - 17天升高，并在31天时超过成年值。HO在出生后无变化。我们得出结论，TO的每种酶都遵循独特的发育路径，整个TO系统没有协同控制。
