Casein labelled with iodine-131 as a substrate for the measurement of trypsin and chymotrypsin

ABSTRACT THE spectrophotometrie method of Kunitz1is a marked improvement over previous methods for the measurement of trypsin and chymotrypsin activity. This procedure involves a measurement

of the optical density at 280 mµ. of the trichloracetic acid-soluble products formed during the enzyme hydrolysis of casein; it becomes impractical, however, where large concentrations of

280 mµ absorbing materials are present, such as in sera. In this communication, a modification of this procedure will be described which utilizes casein labelled with iodine-131 as the

substrate and the measurement of radioactivity as an estimate of enzyme activity. Access through your institution Buy or subscribe This is a preview of subscription content, access via your

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Α-CHYMOTRYPSIN Article Open access 16 August 2021 SINGLE TIME-POINT ANALYSIS OF PRODUCT AND SUBSTRATE INHIBITION Article Open access 05 October 2024 THE MEASUREMENT OF TRUE INITIAL RATES IS

NOT ALWAYS ABSOLUTELY NECESSARY TO ESTIMATE ENZYME KINETIC PARAMETERS Article Open access 12 September 2023 REFERENCES * Kunitz, M., _J. Gen. Physiol._, 30, 291 (1947). Article  CAS  Google

Scholar  Download references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Research, Miami Valley Hospital, Dayton, Ohio BERNARD J. KATCHMAN, ROBERT E. ZIPF & GEORGE M.

HOMER Authors * BERNARD J. KATCHMAN View author publications You can also search for this author inPubMed Google Scholar * ROBERT E. ZIPF View author publications You can also search for

this author inPubMed Google Scholar * GEORGE M. HOMER View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions

ABOUT THIS ARTICLE CITE THIS ARTICLE KATCHMAN, B., ZIPF, R. & HOMER, G. Casein labelled with Iodine-131 as a Substrate for the Measurement of Trypsin and Chymotrypsin. _Nature_ 185,

238–239 (1960). https://doi.org/10.1038/185238a0 Download citation * Issue Date: 23 January 1960 * DOI: https://doi.org/10.1038/185238a0 SHARE THIS ARTICLE Anyone you share the following

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