An Iron-containing Phosphatase Induced by Progesterone in the Uterine Fluids of Pigs

Schlosnagle, David C.; Bazer, Fuller W.; Tsibris, John C.M.; Roberts, R. Michael

doi:10.1016/s0021-9258(19)81276-0

Cited by 145 publications

(18 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As indicated by their name, all PAPs characterized thus far show optimal activity under mildly acidic conditions. Activity vs pH profiles have been reported for Uf (36,39), BSPAP (4,11,32), KBPAP (46,47), and several other mammalian PAPs ((48) and references therein) using a variety of substrates and conditions. The pH optima reported range from pH 5.0, typically found for Uf, to pH 6.3 for both FeFe-and FeZn-forms of BSPAP (when assayed at 50 mM p-NPP).…”

Section: Discussionmentioning

confidence: 99%

Evidence for Nonbridged Coordination of p-Nitrophenyl Phosphate to the Dinuclear Fe(III)−M(II) Center in Bovine Spleen Purple Acid Phosphatase during Enzymatic Turnover

1999

View full text Add to dashboard Cite

The pH dependence of the catalytic parameters k(cat) and K(M) has been determined for the Fe(III)Fe(II)- and Fe(III)Zn(II)-forms of bovine spleen purple acid phosphatase (BSPAP). The parameter k(cat) was found to be maximal at pH 6.3, and a pK(a) of 5.4-5.5 was obtained for the acidic limb of the k(cat) vs pH profile. Two different EPR spectra were detected for the phosphate complex of the mixed-valent diiron enzyme; their relative amounts depended on the pH, with an apparent pK(a) of 6. The EPR spectra of Fe(III)Fe(II)-BSPAP.PO(4) and Fe(III)Zn(II)-BSPAP.PO(4) at pH 5.0 are similar to those previously reported for Fe(III)Fe(II)-Uf.PO(4) and Fe(III)Zn(II)-Uf.PO(4) complexes at pH 5.0. At higher pH, a new Fe(III)Fe(II)-BSPAP.PO(4) species is formed, with apparent g-values of 1.94, 1.71, and 1.50. The EPR spectrum of Fe(III)Zn(II)-BSPAP does not show significant changes upon addition of phosphate up to 30 mM at pH 6.5, suggesting that phosphate binds only to the spectroscopically silent Zn(II). To determine whether the phosphate complexes were good structural models for the enzyme substrate complexes, these complexes were studied using rapid-freeze EPR and stopped-flow optical spectroscopy. The stopped-flow studies showed the absence of burst kinetics at pH 7.0, which indicates that substrate hydrolysis is rate limiting, rather than phosphate release. The EPR spectrum of Fe(III)Fe(II)-BSPAP.p-NPP is similar, but not identical, to that of the corresponding phosphate complex, both at pH 5 and pH 6.5. We propose that both phosphate and p-NPP bridge the two metal ions at low pH. At higher pH where the enzyme is optimally active, we propose that hydroxide competes with phosphate and p-NPP for coordination to Fe(III) and that both phosphate and p-NPP coordinate only to the divalent metal ion.

show abstract

Section: Discussionmentioning

confidence: 99%

Evidence for Nonbridged Coordination of p-Nitrophenyl Phosphate to the Dinuclear Fe(III)−M(II) Center in Bovine Spleen Purple Acid Phosphatase during Enzymatic Turnover

1999

View full text Add to dashboard Cite

show abstract

“…Spectrometer conditions: microwave frequency, 9.443 GHz; modulation amplitude, 10 G at 100 kHz; microwave power, 20 mW. ) -440 mV) (Averill et al, 1987;Schlosnagle et al, 1974). Additional equivalents of dithionite, however, lead to bleaching of the color, loss of the mixed valence EPR resonance, and loss of iron from the sample (Schlosnagle et al, 1976;Averill et al, 1987).…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic and Enzymatic Characterization of the Active Site Dinuclear Metal Center of Calcineurin: Implications for a Mechanistic Role

Golbeck

Yao

et al. 1997

Biochemistry

View full text Add to dashboard Cite

The active site of bovine brain calcineurin contains an Fe3+-Zn2+ dinuclear metal center. Replacement of Zn2+ with Fe2+ yields a mixed valence Fe3+-Fe2+ center that exhibits a characteristic EPR signal that can be used as a convenient spectroscopic probe of the active site. Addition of product phosphate to both the Fe3+-Fe2+ and Fe3+-Zn2+ forms of calcineurin led to perturbations of the respective EPR signals, indicating that phosphate affects the environment of the paramagnetic centers. Anaerobic titrations of the iron-substituted Fe3+-Fe2+ enzyme with dithionite resulted in a gradual loss of activity toward pNPP that paralleled the loss of intensity of the EPR signal of the mixed valence diiron center. During dithionite reduction, an EPR resonance with g approximately 12 appeared. The intensity of this resonance increased when the spectrum was recorded in a parallel mode cavity and was therefore attributed to a paramagnetic center with integer spin. Oxidation of the Fe3+-Fe2+ cluster to the diferric state by hydrogen peroxide also led to a loss of activity. These results indicate that the mixed valence oxidation state represents the catalytically competent form of the cluster. The dependence of the enzyme activity on the redox state of the cluster has implications for a mechanistic role.

show abstract

“…Iron is provided to the fetus by the secretion of uteroferrin (Roberts et al, 1987;Roberts and Bazer, 1988) by the endometrium. Uteroferrin is a 35,000 Mr protein which contains two irons (Schlosnagle et al, 1974). It exists in two forms within the uterine environment, a purple and a pink form, depending on the redox state of the duron center (Schlosnagle et al, 1976).…”

Section: Fetal Erythropoiesis Requires Specific Uterine Productsmentioning

confidence: 99%

Fetal Erythropoiesis and Other Factors which Influence Uterine Capacity in Swine

Vallet

2000

Journal of Applied Animal Research

View full text Add to dashboard Cite

Large litter size of healthy piglets at weaniwg is an important aspect of swiiie production efficiericy. this is influeitced by several factors like ovulation rate, fertilization rate, early einbryoiric mortality aiid utriite capacity. Several studies showed that iioiie of the single trait is effective to iiiflueiice the productioit efficiericy. Geiietic selectioii iii association with horinoiial inaiaipulatioiis to reduce placental size aiid iiacrease its efficieiicy has beeii found effective. The uteriite capacity is also irnproved through the iinproveineut of fetal erythropoiesis during early as well as late gestatioi~ due to use of geiietic selection, marlier assisted selection or other treatments. Increased uterine capacity may be useful for increasing litter size wheii treatments are applied for increasing the iiuinber of anailable embryos either by iiicreasii~g ovulatiou rate and decreasiiig ernbryomic inorta,lity or transfer of viable embryos.

show abstract

An Iron-containing Phosphatase Induced by Progesterone in the Uterine Fluids of Pigs

Cited by 145 publications

References 28 publications

Evidence for Nonbridged Coordination of p-Nitrophenyl Phosphate to the Dinuclear Fe(III)−M(II) Center in Bovine Spleen Purple Acid Phosphatase during Enzymatic Turnover

Evidence for Nonbridged Coordination of p-Nitrophenyl Phosphate to the Dinuclear Fe(III)−M(II) Center in Bovine Spleen Purple Acid Phosphatase during Enzymatic Turnover

Spectroscopic and Enzymatic Characterization of the Active Site Dinuclear Metal Center of Calcineurin: Implications for a Mechanistic Role

Fetal Erythropoiesis and Other Factors which Influence Uterine Capacity in Swine

Contact Info

Product

Resources

About