Method and apparatus for the determination of enzyme activity

The method of determining enzyme activity in a given sample by plural light-extinction measurements on the sample, which comprises performing a predetermined relatively rapid sequence of plural extinction measurements at a first point in time, repeating said relatively rapid sequence of measurements at second and succeeding relatively greatly spaced points in time, computing the mean value to establish a measurement point for the plural measurements of each such rapid sequence, establishing a regression curve through the said measurement points, taking the tangent of said curve at a particular point in time, and calculating from the slope of this tangent the enzyme activity sought in which enzyme activity of each of a plurality of cell-supported samples is measured, by indexing such cells successively into measurement position for the said first-point sequence of measurements on all samples prior to performing the second-point sequence of measurements on all samples, whereby the plural time-spaced sequences of one sample are time-interlaced with the corresponding time-spaced sequences of another sample.

The method of determining enzyme activity in a given sample by plural light-extinction measurements on the sample, which comprises performing a predetermined relatively rapid sequence of plural extinction measurements at a first point in time, repeating said relatively rapid sequence of measurements at second and succeeding relatively greatly spaced points in time, computing the mean value to establish a measurement point for the plural measurements of each such rapid sequence, establishing a regression curve through the said measurement points, taking the tangent of said curve at a particular point in time, and calculating from the slope of this tangent the enzyme activity sought, in which clock-pulse signals are used to determine precisely-spaced like periods of time between said measurement points.

The method of determining enzyme activity in a given sample by plural light-extinction measurements on the sample, which comprises performing a predetermined relatively rapid sequence of plural extinction measurements at a first point in time, repeating said relatively rapid sequence of measurements at second and succeeding relatively greatly spaced points in time, computing the mean value to establish a measurement point for the plural measurements of each such rapid sequence, establishing a regression curve through the said measurement points, taking the tangent of said curve at a particular point in time, and calculating from the slope of this tangent the enzyme activity sought, in which the regression curve is selected as a second-degree polynomial.

Apparatus for light-extinction measurement of enzyme activity in a sample, comprising a light source, photometer means spaced from and oriented for electrical response to light from said source, sample-supporting means interposed between said source and photometer means, analog-digital converter means connected to the electrical output of said photometer means, computer means connected to control a predetermined rapid sequence of measurements at each of a plurality of spaced points in time, said converter means being connected to said computer means, and said computer means including means for computing and storing the mean value for the collective measurements of each such sequence and for computing the enzyme activity using said stored measurement values.

In combination in enzyme activity determining means, light source and light detector means for determining relative light transmissivity of a sample disposed therebetween, means for repetitively sampling the output of said detector means at spaced points in time relatively large in comparison to the inter-sample interval for any said point in time, computer means for receiving said sampled detector output signals, said computer means including means for determining statistical light transmissivity for the samples at any point in time, means for fitting a curve to said statistical properties determined by said means therefor, and means for determining the derivative of said curve determined by said curve fitting means.