Importance

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Abstract

Tripeptide derivatives having the formula ##STR1## wherein R.sup.1 is alkanoyl or .omega.-aminoalkyanoyl, phenylalkanoyl or p-aminophenylalkanoyl, cyclohexylcarbonyl or 4-aminomethyl-cylcohexylcarbonyl, benzoyl optionally substituted with methyl, amino, or halogen in the o- or p-position, alkoxy carbonyl, benzyloxy carbonyl optionally substituted with methoxy, methyl, or chlorine in the p-position, alkylsulfonyl, phenylsulfonyl or naphthylsulfonyl, R.sup.2 is straight-chained or branched alkyl, hydroxyalkyl, alkoxyalkyl, benzoxyalkyl, .omega.-carboxy-alkyl, .omega.-alkoxy carbonylalkyl, .omega.-benzyloxycarbonylalkyl, cyclohexyl, cyclohexylmethyl, 4-hydroxycyclohexylmethyl, phenyl, benzyl, 4-hydroxybenzyl or imidazol-4-yl-methyl, R.sup.3 is hydrogen or alkyl, R.sup.4 is hydrogen, methyl or ethyl, and R.sub.5 is an amino group substituted with aromatic or heterocyclic radicals, R.sup.5 being capable of being split off by enzymatic hydrolysis to form a colored or fluorescent product H-R.sup.5. The tripeptide derivatives of formula I are used for assaying certain enzymes, and in particular, factor Xa. Enzyme-bearing materials are reacted with the said tripeptide derivatives. The quantity of split product H-R.sub.5 released by the enzymatic action on the tripeptide derivative is determined photometrically, spectrophotometrically, fluorescence-spectrophotometrically, or electrochemically. The quantity of released split product H-R.sup.5 per time unit is proportional to the quantity of enzyme present in the starting material.

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First Claim