Michaelis constant


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Mi·chae·lis con·stant

(mi-kā'lis),
1. the true dissociation constant for the enzyme-substrate binary complex in a single-substrate rapid equilibrium enzyme-catalyzed reaction (usually symbolized by Ks);
2. the concentration of the substrate at which half the true maximum velocity of an enzyme-catalyzed reaction is achieved (when velocities are measured under initial rate and steady-state conditions); the ratio of rate constants (k2 + k3)/k1 in the single-substrate enzyme-catalyzed reaction: E + S ⇄ ES ⇄ E + products, where E represents the free enzyme, S is the substrate, and ES is the central binary complex. The expression for the Michaelis constant will be more complex for multisubstrate reactions. An apparent Michaelis constant is a constant determined either under conditions that are not strictly steady-state and initial rate or under a condition that varies with the concentration of one or more cosubstrates.
[Leonor Michaelis]

Mi·chae·lis con·stant

(mi-kā'lis kon'stănt)
1. The true dissociation constant for the enzyme-substrate binary complex in a single-substrate rapid equilibrium enzyme-catalyzed reaction (usually symbolized by Ks).
2. The concentration of the substrate at which half the true maximum velocity of an enzyme-catalyzed reaction is achieved.
[Leonor Michaelis]

Michaelis,

Leonor, German-U.S. chemist and physician, 1875-1949.
Michaelis buffer
Michaelis constant - the true dissociation constant for the enzyme-substrate binary complex in a single-substrate rapid equilibrium enzyme-catalyzed reaction. Synonym(s): Michaelis-Menten constant
Michaelis-Gutmann body - a rounded homogenous body containing calcium and iron found within macrophages in the bladder wall in malacoplakia.
Michaelis-Menten constant - Synonym(s): Michaelis constant
Michaelis-Menten equation - an initial-rate equation for a single-substrate noncooperative enzyme-catalyzed reaction relating the initial velocity to the initial substrate concentration. Synonym(s): Victor-Michaelis-Menten equation
Michaelis-Menten hypothesis - that a complex is formed between an enzyme and its substrate (the O'Sullivan-Tompson hypothesis), which complex then decomposes to yield free enzyme and the reaction products (Brown hypothesis), the latter rate determining the overall rate of substrate-product conversion.
Victor-Michaelis-Menten equation - Synonym(s): Michaelis-Menten equation

Michaelis constant, Michaelis-Mentin constant

see k_7/8 constant.