A method for conforming the pH dependence of the michaelis parameters of nonallosteric enzymes to four kinetic schemes.

A nonlinear regression program for the analysis of the effect of pH on enzyme activity has been developed for the IBM micro range and compatible machines. The program conforms the V and Km pH profiles to one of four commonly occurring kinetic schemes. By using multiple linear regression the program computes initial estimates for the nonlinear search which are thus not required from the user.

A program to estimate insulin sensitivity and pancreatic responsivity from an IVGTT using the minimal modeling technique.

A user-friendly program coded in PASCAL for the IBM PC has been developed to determine the etiology of impaired glucose tolerance using an intravenous glucose tolerance test (IVGTT). It makes use of the "minimal modeling technique," a method that has been shown to be adequate for the quantitative determination of insulin sensitivity and insulin resistance. Two models are used, the minimal model of glucose disappearance and the minimal model of insulin kinetics.

Temperature-jump studies on hemoglobin. Kinetic evidence for a non-quaternary isomerization process in deoxy- and carbonmonoxyhemoglobin.

Temperature jumps on mixtures of hemoglobin and pH indicators give rise to relaxation signals in the microsecond range. The pH and concentration dependences of the reciprocal relaxation time, 1/tau, may be rationalized on the basis of a reaction scheme in which a slow isomerization process in the protein moiety is coupled to a rapid co-operative ionization of two protons. At 11 degrees C the rate constants of the isomerization are kr = 4.

A program for the identification of steady-state processes in biological systems.

A dedicated nonlinear regression program for the identification of steady-state processes is described in detail. Experimental data are fitted to the rational function which describes such systems. The algorithm makes use of parameter separation to relieve the user from the need to assign initial estimates to the linear parameters and to speed up the computation.

The uptake of protons by heme-linked ionizable groups on azide binding to methemoglobin.

When azide ion reacts with methemoglobin in unbuffered solution the pH of the solution increases. This phenomenon is associated with increases in the pK values of heme-linked ionizable groups on the protein which give rise to an uptake of protons from solution. We have determined as a functional of pH the proton uptake, delta h+, on azide binding to methemoglobin at 20 degrees C.