Rapid flow technique

In Eq. (34) the configuration may be either cis or trans and X can be, for example, OH, Cl", F, SCN", or -NH2CH2CH2NH3+ (cf. Table XV). The blue species are unstable, and one cis ammonia ligand in the basic rhodo ion and the X groups in the basic erythro ions are hydrolyzed rapidly in the basic solutions. The Ka values have therefore been determined by a rapid-flow technique in combination with potentio-metric or spectrophotometric measurements (24). 

Hog thyroghbulin exhibits great susceptibility to denaturation at pH values below 4.8 (Heidelberger and Palmer, 1933) and the 0.42 unit shift of its isoelectric point on denaturation (Heidelberger and Pedersen, 1935) suggests that acid titration data should be obtained with a rapid-flow technique for comparison with the titration curve of the denatured protein. 

A stable enzyme-D-glucose intermediate has been obtained in the hydrolysis of methyl a-D-[ C]glucopyranoside by an a-D-glucosidase from Saccharomyces oviformis Phenol was used to terminate the reaction and to trap the intermediate in a rapid-flow technique. The intermediate appears to be covalently linked, since continuous washing of the denatured protein failed to remove the radiolabel, which was also retained by a tryptic peptide isolated by gel filtration. Treatment of the intermediate with acid released D-[ C]glucose. The radiolabel was not bound when the enzyme was replaced with bovine albumin or when jS-D-glucosylamine (a potent inhibitor of a-D-glucosidase) was added with the enzyme. 

Fig. 8C. The disappearance of leucomalachite green and the kinetics of peroxidase complex II in a mirror oscillograph recording of the rapid flow technique. Time markers are 0.2 second, pH 4.0 (7) (MC-10).

The study of enzyme mechanisms on a time scale of milliseconds became possible when the rapid flow techniques of Hartridge Roughton... 

Since the original work of Hartridge and Houghton, Millikan (136) has adapted the rapid-flow technique for use with small amounts of material and has employed it to study the reactions of purified horse t oThe observation that Am(CO), A,// GO, and AmCOs) are independent of pH, whereas Ao//(Oi) is not, appears inconsistent with the fact that the partition coefficient a is independent of pH. 

Using a rapid flow technique, where a jet of molecules solved in a liquid flows through a focused laser beam, it is possible to study also photolabile molecules, such as rhodopsin, by resonance Raman spectroscopy [14.32]. This allows investigation of the interesting problem about the molecular mechanisms and dynamics of visual excitation. Rhodopsin molecules act as photoreceptors in the retina of vertebrates. If the rhodopsin sample is rapidly flowed through the focused laser beam, the fraction of isomerized molecules within the illuminated region stays small. This allows measurement of the resonance... 

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