Synthesis of prostaglandin F ethanolamide by prostaglandin F synthase and identification of Bimatoprost as a potent inhibitor of the enzyme: new enzyme assay method using LC/ESI/MS

2004 ◽  
Vol 424 (2) ◽  
pp. 128-136 ◽  
Author(s):  
Noriko Koda ◽  
Yasutaka Tsutsui ◽  
Haruki Niwa ◽  
Seiji Ito ◽  
David F Woodward ◽  
...  
Keyword(s):  
Enzyme Assay ◽  
Potent Inhibitor ◽  
Assay Method ◽  
Esi Ms ◽  
Prostaglandin F

Measurement of Bone-Specific Alkaline Phosphatase by an Immunoselective Enzyme Assay Method

1996 ◽  
Vol 33 (2) ◽  
pp. 127-131 ◽  
Author(s):  
Keishi Hata ◽  
Hisako Tokuhiro ◽  
Kiyoshi Nakatsuka ◽  
Takami Miki ◽  
Yoshiki Nishizawà ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Assay ◽  
Metabolic Diseases ◽  
Clinical Investigation ◽  
Assay Method ◽  
Osteosarcoma Cell ◽  
Electrophoretic Method ◽  
Specific Alkaline Phosphatase ◽  
Bone Specific Alkaline Phosphatase ◽  
Age Related

We evaluated a new immunoselective enzyme assay of bone-specific alkaline phosphatase (ALP). The monoclonal antibody used in this assay was raised against purified bone-specific ALP obtained from SAOS-2 human osteosarcoma cell line. Calibration was based on the enzyme's own activity. The relative activity of the antibody was 100% with bone ALP, 8·7% with liver ALP, and 0% with placental and intestinal ALPs. Intra- and inter-assay coefficients of variation were less than 4%. The sensitivity of the assay was 0·7 U/L, and the linearity extended from 2 to 140 U/L. The recovery of bone-specific ALP standard added to serum was 94–106%. The correlation coefficient between this method and the polyacrylamide gel (PAG) electrophoretic method was 0·94. The mean value of bone-specific ALP in 89 healthy adults (mean age 29 years, SD 5 years) was 18·5 U/L (SD 4·1 U/L). Interestingly, mean bone-specific ALP activities in 60 premenopausal women (mean age 39 years, SD 8 years) and 70 postmenopausal women (mean age 57 years, SD 5 years) were 20·3 U/L (SD 6·5 U/L) and 31·1 U/L (SD 11·1 U/L), respectively. The age-related increase in bone-specific ALP was significant and more pronounced in women ( P < 0·01). We conclude that this new immunoassay of bone-specific ALP would be useful for clinical investigation of patients with osteoporosis or other metabolic diseases of bone.

scholarly journals Assay method for monitoring the inhibitory effects of antimetabolites on the activity of inosinate dehydrogenase in intact human CEM lymphocytes

1992 ◽  
Vol 287 (3) ◽  
pp. 785-790 ◽  
Author(s):  
J Balzarini ◽  
E De Clercq
Keyword(s):  
Mycophenolic Acid ◽  
Marked Effect ◽  
De Novo ◽  
Potent Inhibitor ◽  
Assay Method ◽  
The Novel ◽  
Inhibitory Effects ◽  
Intact Cells ◽  
Imp Dehydrogenase

A rapid and convenient method has been developed to monitor the inhibition of inosinate (IMP) dehydrogenase by antimetabolites in intact human CEM lymphocytes. This method is based on the determination of 3H release from [2,8-3H]hypoxanthine ([2,8-3H]Hx) or [2,8-3H]inosine ([2,8-3H]Ino). The validity of this procedure was assessed by evaluating IMP dehydrogenase inhibition in intact CEM cells by the well-known IMP dehydrogenase inhibitors ribavirin, mycophenolic acid and tiazofurin. As reference materials, several compounds that are targeted at other enzymes in de novo purine nucleotide anabolism (i.e. hadacidine, acivicin) or catabolism (i.e. 8-aminoguanosine, allopurinol) were evaluated. There was a strong correlation between the inhibitory effects of the IMP dehydrogenase inhibitors (ribavirin, mycophenolic acid, tiazofurin) on 3H release from [2,8-3H]Hx and [2,8-3H]Ino in intact CEM cells and their ability to decrease intracellular GTP pool levels. The other compounds (hadacidine, acivicin, 8-aminoguanosine, allopurinol) had no marked effect on 3H release from [2,8-3H]Hx. Using this method, we demonstrated that the novel ribavirin analogue, 5-ethynyl-1-beta-D-ribofuranosylimidazole-4-carboxamide, is a potent inhibitor of IMP dehydrogenase in intact cells.

scholarly journals Ultrahigh-Throughput ESI-MS: Sampling Pushed to Six Samples per Second by Acoustic Ejection Mass Spectrometry

2020 ◽  
Author(s):  
Tim Häbe ◽  
Chang Liu ◽  
Tom Covey ◽  
Roman P. Simon ◽  
Wolfgang Reindl ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Enzyme Assay ◽  
Sampling Rate ◽  
Internal Standard ◽  
Stress Tests ◽  
Esi Ms ◽  
Droplet Ejection ◽  
Signal Suppression ◽  
Dog Plasma ◽  
Open Port

<div> <p> We present an acoustic ejection mass spectrometry (AEMS) setup for ESI-MS based sample </p><p> injection at a sampling rate faster than current ESI and MALDI techniques. A modified acoustic </p><p> droplet ejection system was combined with an open port interface and a modified ESI source. To </p><p> simulate applications of drug metabolism and pharmacokinetics analysis and high-throughput </p><p> screening campaigns, two stress tests were performed regarding ion suppression and system </p><p> endurance in combination with minor sample preparation. Maximum sampling rate was 6 Hz for </p><p> dextromethorphan and d3-dextrorphan (each 100 nM) for 1152 injections in 63 s at FWHM of </p><p> 105 ms and %RSD of 7.7%/7.5% without internal standard correction. Enzyme assay buffer and </p><p> crude dog plasma caused signal suppression of 51%/73% at %RSD of 5.7%/6.7% (n = 120) and </p><p> stable OPI performance during 1100 injections. An endurance buffer revealed minor OPI pollution </p><p> and constant signals for >25.000 injections (%RSD = 8.5%, n = 10,557). </p></div>

scholarly journals Ultrahigh-Throughput ESI-MS: Sampling Pushed to Six Samples per Second by Acoustic Ejection Mass Spectrometry

2020 ◽  
Author(s):  
Tim Häbe ◽  
Chang Liu ◽  
Tom Covey ◽  
Roman P. Simon ◽  
Wolfgang Reindl ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Enzyme Assay ◽  
Sampling Rate ◽  
Internal Standard ◽  
Stress Tests ◽  
Esi Ms ◽  
Droplet Ejection ◽  
Signal Suppression ◽  
Dog Plasma ◽  
Open Port

<div> <p> We present an acoustic ejection mass spectrometry (AEMS) setup for ESI-MS based sample </p><p> injection at a sampling rate faster than current ESI and MALDI techniques. A modified acoustic </p><p> droplet ejection system was combined with an open port interface and a modified ESI source. To </p><p> simulate applications of drug metabolism and pharmacokinetics analysis and high-throughput </p><p> screening campaigns, two stress tests were performed regarding ion suppression and system </p><p> endurance in combination with minor sample preparation. Maximum sampling rate was 6 Hz for </p><p> dextromethorphan and d3-dextrorphan (each 100 nM) for 1152 injections in 63 s at FWHM of </p><p> 105 ms and %RSD of 7.7%/7.5% without internal standard correction. Enzyme assay buffer and </p><p> crude dog plasma caused signal suppression of 51%/73% at %RSD of 5.7%/6.7% (n = 120) and </p><p> stable OPI performance during 1100 injections. An endurance buffer revealed minor OPI pollution </p><p> and constant signals for >25.000 injections (%RSD = 8.5%, n = 10,557). </p></div>

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