What is pA2?
pA2 is a measure of the potency of an antagonist. It is the negative logarithm of the molar concentration of an antagonist that would produce a 2-fold shift in the concentration response curve for an agonist.
How is pA2 measured?
The pA2 is defined as the negative common logarithm of B which produces a dose-ratio of 2; hence, pA2 = -log B = -log KB = 10g(1jKB). Since IjKB is the affinity constant, the pA2 may be viewed as a measure of affinity.
What is a high pA2 value?
The higher the value for pA2, the higher the affinity of B is to its receptor. For graphic. analysis, one can plot log (DR–1) against log ([B]), yielding a linear relationship that. can be analysed by linear regression.
What is pA2 and pd2 value explain its importance?
pA2 value • Measure for the equilibrium dissociation constant of the antagonist • Defined as the negative log of molar concentration of the antagonist which will reduce the effect of double dose of the agonist drug to that of a single dose • pAx: x denotes the the number by which the agonist dose has to be increased to …
What is pD2 value?
pD2′ value • Measures the affinity of either non competitive or irreversible competitive antagonist for a specific receptor • Defined as –log(B) which will decrease the maximum effect of agonist by 50% • Higher the pD2 value ,higher the potency.
What is pKI of a drug?
Abstract. Kinases are one of the most important classes of drug targets for therapeutic use. Algorithms that can accurately predict the drug-kinase inhibitor constant (pKi) of ki- nases can considerably accelerate the drug discovery process.
What is IC50 and Ki?
Answer. The value Ki is the dissociation constant describing the binding affinity between the inhibitor and the enzyme, while IC50 is the concentration of inhibitor required to reduce the enzymatic activity to half of the uninhibited value.
What is the difference between KI and KD?
The difference between Kd and Ki is that Kd is a more general, all-encompassing term, whilst Ki is more narrowly used to indicate the dissociation equilibrium constant of the enzyme-inhibitor complex.
What are inhibitory drugs?
Artificial inhibitors are often used as drugs, but can also be insecticides such as malathion, herbicides such as glyphosate, or disinfectants such as triclosan. Other artificial enzyme inhibitors block acetylcholinesterase, an enzyme which breaks down acetylcholine, and are used as nerve agents in chemical warfare.
What drugs are strong CYP3A4 inducers?
Potent inhibitors of CYP3A4 include clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole, ritonavir, verapamil, goldenseal and grapefruit. Inducers of CYP3A4 include phenobarbital, phenytoin, rifampicin, St. John’s Wort and glucocorticoids.
What are 3 types of inhibitors?
There are three kinds of reversible inhibitors: competitive, noncompetitive/mixed, and uncompetitive inhibitors.
Is Penicillin an inhibitor?
Penicillin is an active-site inhibitor for four genera of bacteria.
Is Penicillin a reversible inhibitor?
Penicillin irreversibly inhibits the enzyme transpeptidase by reacting with a serine residue in the transpeptidase. This reaction is irreversible and so the growth of the bacterial cell wall is inhibited.
What diseases does penicillin cure?
Penicillin V potassium is used to treat certain infections caused by bacteria such as pneumonia and other respiratory tract infections, scarlet fever, and ear, skin, gum, mouth, and throat infections.
Why is penicillin called the Queen of drugs?
Penicillin was hailed as a “miracle drug” that could save lives and effectively treat a variety of infectious diseases. Today, there are many natural and synthetic types of penicillin, which are used to treat a wide range of ailments.
What is a natural penicillin?
Natural Penicillins were the first antibiotics used in clinical practice. They are based on the original penicillin- G structure. They inhibit bacterial cell wall synthesis and are generally bactericidal.
What foods produce penicillin?
Some of the fungi most frequently isolated from fermented and cured meat products such as Penicillium chrysogenum and Penicillium nalgiovense are known penicillin producers; the latter has been shown to be able to produce penicillin when growing on the surface of meat products and secrete it to the medium.