scholarly journals Periodate-oxidized AMP as a substrate, an inhibitor and an affinity label of human placental alkaline phosphatase

1981 ◽  
Vol 199 (2) ◽  
pp. 281-287 ◽  
Author(s):  
G G Chang ◽  
S C Wang ◽  
F Pan
Keyword(s):  
Alkaline Phosphatase ◽  
Inorganic Phosphate ◽  
Competitive Inhibitor ◽  
Binary Complex ◽  
Placental Alkaline Phosphatase ◽  
Phosphate Binding ◽  
Complete Inactivation ◽  
Nitrophenyl Phosphate ◽  
Saturation Kinetics ◽  
Human Placental Alkaline Phosphatase

Human placental alkaline phosphatase (EC 3.1.3.1) was inactivated by periodate-oxidized AMP. The inactivation showed saturation kinetics and could be partially prevented by the substrate AMP or the product inhibitor inorganic phosphate. Oxidized AMP was itself a substrate for this enzyme, with an apparent Km of 0.67 mM. The hydrolytic products of oxidized AMP were identified as oxidized adenosine hemiacetals. Oxidized AMP was also found to be a non-competitive inhibitor with respect to p-nitrophenyl phosphate, with identical Kis and Kii values of 0.15 mM. Our results indicate that oxidized AMP could combine with the enzyme to form a binary complex, followed by reaction with the proximal lysyl amino group to yield a Schiff base. The latter was reduced with NaBH4 and identified by t.l.c. The incorporation of only 1.5 molecules of oxidized [14C]AMP per enzyme subunit resulted in a complete inactivation of the enzyme. The modified enzyme showed higher apparent Km for the substrates and higher Ki for inorganic phosphate, but lower [32P]phosphate incorporation, than the native enzyme. These results support the conclusion that a lysine residue is involved in the phosphate-binding site of human placental alkaline phosphatase.

scholarly journals Modification of human placental alkaline phosphatase by periodate-oxidized 1,N6-ethenoadenosine monophosphate

1990 ◽  
Vol 272 (3) ◽  
pp. 683-690 ◽  
Author(s):  
G G Chang ◽  
M S Shiao ◽  
K R Lee ◽  
J J Wu
Keyword(s):  
Alkaline Phosphatase ◽  
Dependent Manner ◽  
Placental Alkaline Phosphatase ◽  
Phosphate Binding ◽  
Hydrophobic Region ◽  
Concentration Dependent Manner ◽  
General Chemical ◽  
Wide Range ◽  
Human Placental Alkaline Phosphatase ◽  
Activity Loss

Oxidation of 1,N6-ethenoadenosine monophosphate (epsilon AMP) with periodate cleaved the cis-diol of the ribose ring and resulted in the formation of a dialdehyde derivative (epsilon AMP-dial). At room temperature epsilon AMP-dial was unstable and underwent beta-elimination to give 4′,5′-anhydro-1,N6-ethenoadenosine dialdehyde acetal (A epsilon Ado-dial). These nucleotide analogues were found to inactivate human placental alkaline phosphatase in a time- and concentration-dependent manner. epsilon AMP-dial was shown to be an affinity label for the enzyme on the basis of the following criteria. (a) Kinetics of the enzyme activity loss over a wide range of epsilon AMP-dial concentration showed a saturating phenomenon. Removal of the phosphate group made the reagent (A epsilon Ado-dial) become a general chemical modifying reagent. (b) The artificial substrate p-nitrophenyl phosphate gave substantial protection of the enzyme against inactivation. (c) epsilon AMP-dial was a substrate and a partial mixed-type inhibitor for the enzyme. Results of the inhibition and protection studies indicated that the reagent and substrate could combine with the enzyme simultaneously. Besides the phosphate-binding domain, an induced hydrophobic region is proposed for the substrate-binding site for human placental alkaline phosphatase.

Involvement of arginine residue in the phosphate binding site of human placental alkaline phosphatase

1981 ◽  
Vol 13 (11) ◽  
pp. 1143-1149 ◽  
Author(s):  
Chueh Sheau-Huei ◽  
Chang Gu-Gang ◽  
Chang Tsu-Chung ◽  
Pan Foo
Keyword(s):  
Alkaline Phosphatase ◽  
Binding Site ◽  
Arginine Residue ◽  
Placental Alkaline Phosphatase ◽  
Phosphate Binding ◽  
Human Placental Alkaline Phosphatase

scholarly journals The Promoter of the Rat Gonadotropin-Releasing Hormone Receptor Gene Directs the Expression of the Human Placental Alkaline Phosphatase Reporter Gene in Gonadotrope Cells in the Anterior Pituitary Gland as well as in Multiple Extrapituitary Tissues

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 983-993 ◽  
Author(s):  
Anne Granger ◽  
Valérie Ngô-Muller ◽  
Christian Bleux ◽  
Céline Guigon ◽  
Hanna Pincas ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Reporter Gene ◽  
Transgene Expression ◽  
Pituitary Cells ◽  
Placental Alkaline Phosphatase ◽  
R Gene ◽  
Glycoprotein Hormone ◽  
Steroidogenic Factor 1 ◽  
Functional Sites ◽  
Human Placental Alkaline Phosphatase

Abstract Previous studies dealing with the mechanisms underlying the tissue-specific and regulated expression of the GnRH receptor (GnRH-R) gene led us to define several cis-acting regulatory sequences in the rat GnRH-R gene promoter. These include functional sites for steroidogenic factor 1, activator protein 1, and motifs related to GATA and LIM homeodomain response elements as demonstrated primarily in transient transfection assays in mouse gonadotrope-derived cell lines. To understand these mechanisms in more depth, we generated transgenic mice bearing the 3.3-kb rat GnRH-R promoter linked to the human placental alkaline phosphatase reporter gene. Here we show that the rat GnRH-R promoter drives the expression of the reporter gene in pituitary cells expressing the LHβ and/or FSHβ subunit but not in TSHβ- or GH-positive cells. Furthermore, the spatial and temporal pattern of the transgene expression during the development of the pituitary was compatible with that characterizing the emergence of the gonadotrope lineage. In particular, transgene expression is colocalized with the expression of the glycoprotein hormone α-subunit at embryonic day 13.5 and with that of steroidogenic factor 1 at later stages of pituitary development. Transgene expression was also found in specific brain areas, such as the lateral septum and the hippocampus. A single promoter is thus capable of directing transcription in highly diverse tissues, raising the question of the different combinations of transcription factors that lead to such a multiple, but nevertheless cell-specific, expressions of the GnRH-R gene.

Polymorphisms of Human Placental Alkaline Phosphatase Are Associated with in Vitro Fertilization Success and Recurrent Pregnancy Loss

2014 ◽  
Vol 184 (2) ◽  
pp. 362-368 ◽  
Author(s):  
Magalie Vatin ◽  
Sylvie Bouvier ◽  
Linda Bellazi ◽  
Xavier Montagutelli ◽  
Paul Laissue ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
In Vitro Fertilization ◽  
Pregnancy Loss ◽  
Recurrent Pregnancy Loss ◽  
Fertilization Success ◽  
Placental Alkaline Phosphatase ◽  
Vitro Fertilization ◽  
Human Placental Alkaline Phosphatase

scholarly journals GnRH Receptor Gene Expression in the Developing Rat Hippocampus: Transcriptional Regulation and Potential Roles in Neuronal Plasticity

Endocrinology ◽  
2010 ◽  
Vol 152 (2) ◽  
pp. 568-580 ◽  
Author(s):  
Anne-Laure Schang ◽  
Valérie Ngô-Muller ◽  
Christian Bleux ◽  
Anne Granger ◽  
Marie-Claude Chenut ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Neuronal Plasticity ◽  
Gnrh Receptor ◽  
Lateral Septum ◽  
Rat Hippocampus ◽  
Marker Genes ◽  
Mrna Levels ◽  
Primary Role ◽  
Placental Alkaline Phosphatase ◽  
Human Placental Alkaline Phosphatase

Abstract In the pituitary of mammals, the GnRH receptor (GnRHR) plays a primary role in the control of reproductive function. It is further expressed in the hippocampus, where its function, however, is not well defined. By quantitative RT-PCR analyses, we demonstrate herein that the onset of GnRHR gene (Gnrhr) expression in the rat hippocampus was unexpectedly delayed as compared to the pituitary and only occurred after birth. Using a previously described transgenic mouse model bearing the human placental alkaline phosphatase reporter gene under the control of the rat Gnrhr promoter, we established a positive correlation between the temporal pattern of Gnrhr mRNA levels and promoter activity in the hippocampal formation. The gradual appearance of human placental alkaline phosphatase transgene expression occurred simultaneously in the hippocampus and interconnected structures such as the lateral septum and the amygdala, coinciding with the establishment of hippocampo-septal projections. Analysis of transcription factors together with transient transfection assays in hippocampal neurons indicated that the combinatorial code governing the hippocampus-specific expression of the Gnrhr is distinct from the pituitary, likely involving transactivating factors such as NUR77, cyclic AMP response element binding protein, and Finkel-Biskis-Jinkins murine osteosarcoma virus oncogene homolog. A silencing transcription factor acting via the -3255/-1135 promoter region of the Gnrhr may be responsible for the transcriptional repression observed around birth. Finally, GnRH directly stimulated via activation of its receptor the expression of several marker genes of neuronal plasticity such as Egr1, synaptophysin, and spinophilin in hippocampal primary cultures, suggesting a role for GnRHR in neuronal plasticity. Further characterization of these mechanisms may help unravel important functions of GnRH/GnRHR signaling in the brain.

scholarly journals Expression of active, membrane-bound human placental alkaline phosphatase by transfected simian cells.

1987 ◽  
Vol 84 (14) ◽  
pp. 4885-4889 ◽  
Author(s):  
J. Berger ◽  
A. D. Howard ◽  
L. Gerber ◽  
B. R. Cullen ◽  
S. Udenfriend
Keyword(s):  
Alkaline Phosphatase ◽  
Placental Alkaline Phosphatase ◽  
Active Membrane ◽  
Human Placental Alkaline Phosphatase ◽  
Membrane Bound
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