Abstract: A process for preparing .alpha.-hydroxy acids represented by the general formula (II): RCH(OH)COOH (wherein R represents a hydrogen atom, an optionally substituted C1-C6 alkyl group, an optionally substituted C2-C6 alkenyl group, an optionally substituted C1-C6 alkoxy group, an optionally substituted aryl group, an optionally substituted aryloxy group, or an optionally substituted heterocyclic group) by allowing a microorganism to act on .alpha.-hydroxy nitriles (I): RCH(OH)CN (wherein R is as defined above) to hydrolyze and convert the .alpha.-hydroxy nitrites to .alpha.-hydroxy acids (II), wherein the .alpha.-hydroxy acids (II) are produced and accumulated in an aqueous solvent by a microorganism having the concentration resistance to the .alpha.-hydroxy nitrites (I) and/or .alpha.-hydroxy acids (II) and durability preferably in the presence of a cyanide, and harvested. According to this process, the use of the microorganism having the concentration resistance to the .alpha.-hydroxy nitriles (I) and/or .

Abstract: Human prourokinase-like polypeptides of which oligopeptides having a structure to form a covalent bond with blood clot (thrombus) through enzymatic action of human blood coagulation factor XIII are attached to the NH.sub.2 -terminal sides of human prourokinase derivatives.