Abbott Laboratories Corporation

Akhtar Ali

Jacob J Plattner

Robert G Hiltibran

Paulus T Tsui

The synthesis, resolution, radiolabeling and determination of the superior immunoreactivity of the syn isomer of a derivative of cortisol-21-acetate is described.

Preferential immunoreactivity of syn-isomer of cortisol derivative

The present invention encompasses compounds I and II, mixtures of I and II and acid addition salts thereof wherein R is hydrogen or loweralkyl having 1-3 carbon atoms, as well as compounds wherein the phenol moiety is labeled with .sup.125 I or .sup.131 I. The radiolabeled compounds are useful in radiochemical assaying for folic acid. ##STR1##

Folic acid derivatives for use in radioimmunoassay

This invention relates to the synthesis and use of novel .alpha. hydroxy tripeptide substrates which are useful in the quantitative determination of proteolytic enzymes such as thrombin and trypsin. In use, the disclosed substrates are hydrolyzed by a proteolytic enzyme to yield a moiety that can be evaluated spectrophotometrically to indicate the quantity of enzyme present.

.alpha. hydroxy tripeptide substrates

The present invention comprises compounds of the formula ##STR1## and the biologically acceptable acid addition salts thereof, wherein R.sub.1 represents hydrogen or lower alkyl having 1 to 4 carbon atoms; R.sub.2 represents an alkylene having 2 to 4 carbon atoms; R.sub.3 represents amino or guanidino; R.sub.4 represents nitrophenyl, methylnitrophenyl, dinitropheyl, naphthyl, or nitronaphtyl; m is 2 or 3; and n is 3 or 4. The compounds of the present invention are analytical reagents useful for measuring proteolytic enzymes such as thrombin and trypsin. The enzymatic hydrolysis of the invention compounds provides a chromogenic amine by which the proteolytic enzyme concentration can be determined spectrophotometrically.

Chromogenic substrates

The present invention encompasses a compound of the formula ##STR1## and the biologically acceptable acid addition salts thereof wherein R is hydrogen, tosyl, carbobenzoxy or benzoyl. These compounds are chromogenic substrates for proteolytic enzymes useful in antithrombin III determination.

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Vernon Hills, IL, United States of America

Akhtar Ali