(R)-Nepicastat HCl 195881-94-8

.cp_wz table {border-top: 1px solid #ccc;border-left:1px solid #ccc; } .cp_wz table td{border-right: 1px solid #ccc; border-bottom: 1px solid #ccc; padding: 5px 0px 0px 5px;} .cp_wz table th {border-right: 1px solid #ccc;border-bottom: 1px solid #ccc; padding: 5px 0px 0px 5px;}


Molecular Weight:

331.81 (R)-Nepicastat HCl, the R-enantiomer of Nepicastat HCl, is a potent and selective inhibitor with IC50 of 25.1 nM and 18.3 nM for bovine and human dopamine-β-hydroxylase, with negligible affinity for twelve other enzymes and thirteen neurotransmitter receptors.






Biological Activity


(R)-Nepicastat produces concentration-dependent inhibition of bovine and human dopamine-β-hydroxylase activity in vitro.


(R)-Nepicastat (30 mg/kg, p.o.) reduces noradrenaline content, dopamine
content and dopamine/noradrenaline ratio in mesenteric artery and left
ventricle of spontaneously hypertensive rats (SHRs).






In vitro studies


Bovine and human dopamine-beta-hydroxylase activity are assayed by
measuring the conversion of tyramine to octopamine. Human
dopamine-beta-hydroxylase is purified from the culture medium of the
neuroblastoma cell line SK-N-SH. The assay is performed at pH 5.2 and
32°C in a medium containing 0.125 M sodium acetate, 10 mM fumarate, 0.5 ±
2 μM CuSO4, 0.1 mg/mL catalase, 0.1 mM tyramine and 4 mM ascorbate.


In a
typical assay, 0.5 ± 1 mu of enzyme are added to the reaction mixture
and, subsequently, a substrate mixture containing catalase, tyramine and
ascorbate is added to initiate the reaction (final volume of 0.2 mL).
Samples are incubated with or without the appropriate concentration of
nepicastat (RS-25560-197, S-enantiomer) or RS-25560-198 (R-enantiomer)
at 37 °C for 30-40 minutes.


The reaction is quenched by the stop
solution containing 25 mM EDTA and 240 μM 3-hydroxytyramine (internal
standard). The samples are analysed for octopamine by reverse phase high
pressure liquid chromatography (h.p.l.c.) with ultraviolet
(u.v.)-detection at 280 nM. The h.p.l.c. run is carried out at a flow
rate of 1 mL/min with a LiChroCART 125-4 RP-18 column and isocratic
elution with 10 mM acetic acid, 10 mM 1-heptane sulphonic acid, 12 mM
tetrabutyl ammonium phosphate and 10% methanol.


The remaining % activity
is calculated based on controls (without RS 25560), corrected with
internal standards and fitted to a non-linear four-parameter
concentration-response curve. The activity of nepicastat at twelve
selected enzymes and receptors is determined by use of established
assays.


Binding data are analysed by iterative curve-fitting to a four
parameter logistic equation. Ki values are calculated from IC50 values
by the Cheng-Pruso€ equation. Enzyme inhibitory activity is expressed as
IC50 (concentration required to produce 50% inhibition of enzyme
activity).

Contact us if you need more details on 195881-94-8. We are ready to answer your questions on packaging, logistics, certification or any Other aspects about 195881-94-8、195881-94-8. If these products fail to match your need, please contact us and we would like to provide relevant information.

Product Categories : Metabolism > Hydroxylase Inhibitor