Michaelis-Menten model
Usage
SSmicmen(input, Vm, K)
Arguments
input
|
a numeric vector of values at which to evaluate the model.
|
Vm
|
a numeric parameter representing the maximum value of the response.
|
K
|
a numeric parameter representing the input value at
which half the maximum response is attained. In the field of enzyme
kinetics this is called the Michaelis parameter.
|
Description
This selfStart
model evaluates the Michaelis-Menten model and
its gradient. It has an initial
attribute that
will evaluate initial estimates of the parameters Vm
and K
Value
a numeric vector of the same length as input
. It is the value of
the expression Vm*input/(K+input)
. If both
the arguments Vm
and K
are
names of objects, as opposed to expressions or explicit numerical
values, the gradient matrix with respect to these names is attached as
an attribute named gradient
.Author(s)
Jose Pinheiro and Douglas BatesSee Also
nls
, selfStart
Examples
library( lme )
data( Puromycin )
PurTrt <- Puromycin[ Puromycin$state == "treated", ]
SSmicmen( PurTrt$conc, 200, 0.05 ) # response only
Vm <- 200
K <- 0.05
SSmicmen( PurTrt$conc, Vm, K ) # response and gradient