Properties of soluble and particulate cysteine sulfinate decarboxylase of the adult and the developing rat brain

In order to investigate the mechanisms by which cyst(e)ine (referring in the following to the mixture, in any proportion, of the sulfhydryl form of this compound – cysteine -and the disulfide form – cystine) transfer across the placenta to the fetus might be limited we first assessed the original observation that cyst(e)ine concentrations in fetal plasma are less than or equal to maternal cyst(e)ine concentrations. Second, we determined the capacity of the placenta to concentrate cyst(e)ine. And third, using an animal model, we determined the effects of providing excess cysteine to maternal rats on maternal-fetal cyst(e)ine transfer. Our data confirm (1) that cyst(e)ine is present in concentrations in human cord plasma that are equal to maternal plasma cyst(e)ine concentrations; (2) establish that cyst(e)ine is concentrated in the placenta, and (3) suggest that the incorporation of cyst(e)ine into glutathione in the placenta may limit the transfer of cyst(e)ine to the fetus.

Section: Discussionsupporting

confidence: 81%

Maternal-Fetal Cyst(e)ine Transfer

Malloy¹,

Rassin²,

McGanity³

1983

“…1), cysteine dioxygenase (EC 1.12.11.20) and cysteinesulfinate decarboxylase (EC 4.1.1.29) (13)(14)(15). is accompanied by rela tively high concentrations of taurine in fetal and neonatal tissues [1-4.…”

Section: Introductionmentioning

confidence: 99%

Changes in Cysteine Dioxygenase and Cysteinesulfinate Decarboxylase Activities and Taurine Levels in Tissues of Pregnant or Lactating Rat Dams and Their Fetuses or Pups

Kuo¹,

Stipanuk²

1984

The level of taurine and the activities of the two enzymes involved in its synthesis, cysteine dioxygenase and cysteinesulfinate decarboxylase, were measured in tissues of rat dams during pregnancy and lactation and in their fetuses or pups. The most marked changes observed in the dams included an increased hepatic taurine concentration in late pregnancy (20 days), a decreased plasma taurine concentration during late pregnancy and throughout lactation, and a decrease in tissue cysteine dioxygenase activity in late lactation (20 days). These observations suggest that the dam’s taurine pools may be an important source of taurine for secretion in the milk and that pregnant dams may prepare for the onset of lactation by accumulating additional taurine in the liver. There was little if any correlation between the activities of either of these key enzymes in taurine synthesis and tissue taurine levels. The taurine concentrations in liver, brain, heart and plasma of the young decreased between 1 day before birth and 20 days of age. Cysteine dioxygenase and cysteinesulfinate decarboxylase specific activities increased in the brains of pups between birth and 20 days of age, and cysteinesulfinate decarboxylase activity increased in the livers of pups between birth and 20 days of age. Cysteinesulfinate decarboxylase activity in 80-day-old male rats was more than six times that in female littermates, but no effects of sex on cysteine dioxygenase activity or tissue taurine concentrations were observed.

“…Cystathionine y-lyase (EC 4.4.1.1) is present in human fetal and premature infant liver only at trace levels [3][4][5][6][7], but is present in fetal kidney at two-thirds the specific ac tivity of mature kidney [7], Hepatic cysta thionine p-synthase (EC 4.2.1.22) specific ac tivity is about 20% of the adult level in human fetal tissue [3]. Both cysteine dioxy genase (EC 1.13.11.21) and cysteine sulfinate decarboxylase (4.1.1.29) activities in prenatal (-2 days) and postnatal (0-2 days) rat liver and brain are less than 20% of the mean adult specific activities [8][9][10][11]. Cystathionine y-lyase, cystathionine p-synthase, cysteine dioxyger.ase.…”

Section: Introductionmentioning

confidence: 99%

Developmental Pattern, Tissue Distribution, and Subcellular Distribution of Cysteine: α-Ketoglutarate Aminotransferase and 3-Mercaptopyruvate Sulfurtransferase Activities in the Rat

Kuo

Lea

Stipanuk³

1983

The tissue distribution, the subcellular distribution in liver, and the developmental patterns of cysteine:α-ketoglutarate aminotransferase (CAT) and 3-mercaptopyruvate sulfurtransferase (MPST) activities were determined in rats of the Sprague-Dawley strain. CAT activity was highest in heart and liver, whereas MPST activity was highest in liver and kidney. CAT activity was located primarily in the mitochondrial fraction with a low level of activity in all other fractions. MPST activity was located in both the mitochondrial and cytosolic fractions. The specific activity of CAT and MPST generally increased in rat liver, heart, and kidney during the developmental period from 18 days of gestation to 26 days after birth. Peak CAT-specific activity occurred at about 4 days of age and peak MPST activity occurred at about 21 days of age; peak activity of both CAT and MPST exceeded the adult specific activities. The distribution and developmental pattern of hydrogen sulfide production from cysteine, catalyzed by the coupled activities of CAT and MPST, was similar to those of CAT activity.