PubMed · 587272
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J Byrne. 1977. Liver function studies, part II. Conjugation and excretion tests.. https://pubmed.ncbi.nlm.nih.gov/587272/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The method of chemical assay of angiotensin I-converting enzyme described is a modification of the previously published spectrophotometric assay based on quantitation of hippuric acid released from hippuryl-L-histidyl-L-leucine. The new procedure involves extraction of hippuric acid with ethylacetate, evaporation to dryness of the extract, solubilization of the residue with 1 mol/l NaCl and purification with petroleum ether before measurements of the absorbance at 228 nm of the aqueous phase. Under these conditions, hippuric acid insoluble in petroleum ether remains in the aqueous phase, whereas other A228-absorbing materials, readily soluble in the ether and able to interfere with the assay, are eliminated.
The clinical relevance of the clearance of radiopharmaca is controversial in literature. The cause for this are in our opinion the different methods of evaluation which either make difficult or make impossible a comparison of individual results. The late phase of the disappearance (at least 70 and 100 min p.i.) possesses a high value under the aspect of renal diagnosis, since by its means with a high approximation the renal function may be established itself.
Resonance Raman spectra were obtained of the dithioacyl-enzyme intermediate produced during the papain-catalayzed hydrolysis of methyl thionohippurate. Intense resonance Raman features were observed in (formula; see text) and (formula; see text) stretching regions from the intermediate's (formula; see text) chromophore. These results demonstrate that by using a single atom replacement, i.e. sulfur for oxygen, the catalytically crucial bonds in the ester moiety can be monitored during enzymolysis via the resonance Raman spectrum. The method can be extended to other enzymes whose catalytic mechanisms involve the formation of a thiol-acyl intermediate.