scholarly journals Gly429 is the major determinant of uncompetitive inhibition of human germ cell alkaline phosphatase by l-leucine

1991 ◽  
Vol 274 (1) ◽  
pp. 91-95 ◽  
Author(s):  
C Hummer ◽  
J L Millán
Keyword(s):  
Alkaline Phosphatase ◽  
Catalytic Activity ◽  
Germ Cell ◽  
Major Determinant ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Placental Alkaline Phosphatase ◽  
Uncompetitive Inhibition ◽  
Primary Determinant ◽  
Human Placental Alkaline Phosphatase

The catalytic activity of human placental alkaline phosphatase (PLAP) and germ cell alkaline phosphatase (GCAP) can be inhibited, through an uncompetitive mechanism, by L-Phe. GCAP is also selectively inhibited by L-Leu. Site-directed mutagenesis of five of the 12 residues which are different in PLAP and GCAP revealed that Gly429 is the primary determinant of GCAP inhibition by L-Leu, and Ser84 and Leu297 play a modulatory role in the inhibition.

scholarly journals GCT-06. DIAGNOSIS OF A RARE CASE OF RECURRENT GERM CELL TUMOR BY CSF PLACENTAL ALKALINE PHOSPHATASE PRESENTING WITH DIFFUSE INTRAAXIAL ABNORMALITY IN THE LOWER BRAINSTEM

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii329-iii329
Author(s):  
Hiroki Yamada ◽  
Tomohiro Abiko ◽  
Hirokazu Fujiwara ◽  
Kazunari Yoshida ◽  
Hikaru Sasaki
Keyword(s):  
Alkaline Phosphatase ◽  
Germ Cell ◽  
Germ Cell Tumor ◽  
Rare Case ◽  
Cervical Spinal Cord ◽  
Germ Cell Tumors ◽  
Cell Tumor ◽  
Placental Alkaline Phosphatase ◽  
Steroid Pulse ◽  
Platinum Based Chemotherapy

Abstract INTRODUCTION Germ cell tumors in the central nervous system (CNS) typically arise either at suprasellar and/or pineal region, and occasionally at basal ganglia. We report a case of diagnostically challenging, recurrent germ cell tumor presented with diffuse intraaxial abnormality in and across the lower brainstem, which was diagnosed by the elevated placental alkaline phosphatase (PLAP) level in cerebrospinal fluid (CSF). CASE DESCRIPTION: A 28-year-old man had been treated by chemoradiotherapy at the previous hospital for bifocal suprasellar and pineal lesions with the provisional diagnosis of germinoma without histological confirmation. Three years later, he presented with progressive weakness of bilateral extremities for weeks. Magnetic resonance imaging showed a diffuse, bilaterally symmetric high intensity lesion on T2-weighted image with slight contrast enhancement across the ventral side of the medulla oblongata to the upper cervical spinal cord. Serum and CSF hCG, hCG-β, and AFP were all negative. Since the image findings were atypical for recurrent germ cell tumor, some kind of myelitis was initially suspected. Therefore, steroid pulse therapy was administered. However, the patient’s symptom was still gradually progressing. Then, the CSF PLAP turned out to be positive, indicating the recurrence of germinoma. Accordingly, platinum-based chemotherapy was administered, and the imaging findings, patient’s symptoms, and CSF PLAP began to improve. The patient is to be treated with radiotherapy following chemotherapy. CONCLUSION We report a rare case of CNS germ cell tumor that presented with diffuse intraaxial lesion in the lower brainstem in which examination of CSF PLAP was extremely useful.

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.

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