Possible involvement of placental proteases in bradykinin (BK) degradation

The hydrolysis of bradykinin (BK) by human placental subcellular fractions and pregnancy sera was studied in the presence of inhibitors by measuring amino acids liberated from BK by high-performance liquid chromatography. The effects of the inhibitors DL-2- mercaptomethyl-3-guanidinoethylthiopropionic acid (MGTA, for kininase I), phosphoramidon (for endopeptidase 24.11) and captopril and rentiapril (for angiotensin-converting enzyme [ACE, kininase II]) suggested the essential roles of the above three proteases in BK degradation: among the three proteases, kininase I and endopeptidase 24.11 appeared to be the most important in kininase action in the placenta microsomes, whereas kininase I and ACE appeared to be the most important in kininase action in the placental cytosol, lysosome and pregnancy serum. Measurements of BK concentrations in the umbilical arterial blood, umbilical venous blood and maternal plasma revealed higher concentrations in the mother than in the fetus. The present data suggest that degradation of BK in the placenta and pregnancy serum might contribute to the gradient of BK between mother and fetus.

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Acid hydrolysis of silk fibroins and determination of the enrichment of isotopically labeled amino acids using precolumn derivatization and high-performance liquid chromatography–electrospray ionization–mass spectrometry

Analytical Biochemistry ◽

10.1016/s0003-2697(02)00402-5 ◽

2002 ◽

Vol 311 (1) ◽

pp. 19-26 ◽

Cited By ~ 26

Author(s):

Sonja Hess ◽

Jacco van Beek ◽

Lewis K Pannell

Keyword(s):

Mass Spectrometry ◽

Amino Acids ◽

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

High Performance ◽

Precolumn Derivatization ◽

Ionization Mass ◽

Silk Fibroins ◽

Hydrolysis Of

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Degradation of oxytocin by the human placenta: effect of selective inhibitors

Acta Endocrinologica ◽

10.1530/acta.0.1270076 ◽

1992 ◽

Vol 127 (1) ◽

pp. 76-80 ◽

Cited By ~ 6

Author(s):

S Mizutani ◽

H Yokosawa ◽

Y Tomoda

Keyword(s):

Amino Acids ◽

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Human Placenta ◽

High Performance ◽

Selective Inhibitor ◽

Subcellular Fractions ◽

Selective Inhibitors ◽

Aminopeptidase M ◽

Hydrolysis Of

The hydrolysis of oxytocin by human placental subcellular fractions was studied in the presence of selective inhibitors by measuring liberated amino acids by high performance liquid chromatography (HPLC). Oxytocin degradation by microsomal and lysosomal fractions was inhibited by bestatin, amastatin and puromycin. The IC50 values of these inhibitors on oxytocin degradation by both fractions were similar to those of these inhibitors on the human placental aminopeptidase M measured by L-Leu-p-nitroanilide as a substrate (LAP activity), which we reported previously. However, purified aminopeptidase M from human placental microsomal fractions could not liberate any amino acid from oxytocin. Since phosphoramidon (1 μmol/l), a putative metalloendopeptidase inhibitor, and N-benzylcarbonyl-valyl-prolinal (Z-Val-prolinal) (14 μmol/l), a selective inhibitor of post-proline endopeptidase, could not significantly influence the degradation of oxytocin by either subcellular fractions, neither enzyme seems to be actively involved in oxytocin degradation. These results strongly suggested the existence of oxytocinase(s) other than the above three enzymes in microsomal and/or lysosomal fractions of human placenta.

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Study on the hydrolysis process of food and feed samples using high pressure asher (HPA-S) to determine several amino acids by high performance liquid chromatography

Heavy metals and arsenic concentrations in water, agricultural soil, and rice in Ngan Son district, Bac Kan province, Vietnam ◽

10.47866/2615-9252/vjfc.63 ◽

2019 ◽

Vol 2 (2) ◽

pp. 44-50

Author(s):

Chien Dinh Viet ◽

Luyen Nguyen Tien ◽

Hong Ngoc Nguyen Thi ◽

Hieu Pham Cong ◽

Thanh Do Tat ◽

...

Keyword(s):

Amino Acids ◽

High Pressure ◽

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

High Performance ◽

Hydrolysis Process ◽

Food And Feed ◽

The Common ◽

Hydrolysis Of ◽

Feed Samples

The study researchs on the hydrolysis process of food and feed samples using High Pressure Asher (HPA-S) to determine several amino acids by high-performance liquid chromatography (HPLC). HPA-S equipment is mainly used for samples treatment in analysis of metals by spectroscopy. However, the study also found that HPA-S can be used in hydrolysis of food and feed samples in order to analyze amino acids. The temperature of HPA-S equipment could reach 300oC and maintain continuously at 130 bar pressure, completely digetsing the most complex samples matrix within an hour. The successful study of the application of HPA-S to hydrolyze samples in order to analyze amino acids makes the time of sample preparation significantly shorter but still gave the equivalent stability, even higher than the common samples hydrolyzation.

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