Reversibly precipitable, water-soluble polymer conjugates

A water-soluble polymer conjugate, comprising:

• (a) a water-soluble carrier polymer which is completely soluble in water at a temperature in the range of from about 1.degree. C. to 20.degree. C., which is reversibly precipitable from an aqueous solution by raising the temperature and/or by the addition of a salt, and which is completely redissolvable in the aqueous solution by lowering the temperature or salt concentration and wherein the carrier polymer comprises at least one repeating monomer unit selected from the compounds of the formula I:
• ##STR7## in which R.sup.1 and R.sup.3 are identical or different and denote hydrogen or straight-chain or branched C.sub.1 -C.sub.3 -alkyl, and R.sup.2 denotes straight-chain or branched C.sub.1 -C.sub.3 -alkyl, and of at least one other repeating monomer unit selected from the compounds of the formula II, III and IV:
• ##STR8## wherein R.sup.1 is as defined under formula I,
• R.sup.4 is a hydrophobic group and is a straight-chain C.sub.1 -C.sub.6 -alkyl which, in the case of C.sub.3 -C.sub.6 -alkyl radicals, can also be branched or cyclic,
• R.sup.5 is an activated group and is 3,4-epoxycyclohexyl or a substituent of the formula V:
• ##STR9## wherein:
• A is oxygen, sulfur or an NH group,
• R.sup.6 is a --(CH.sub.2).sub.n --Z radical, in which
• n is a number from 1 to 6, and
• Z is amino, hydroxyl, carboxyl, carbonyl or 1,2-epoxyethyl,
• X is a hydrophilic group and is an OH, NH.sub.2 or SH group, and
• Y is oxygen or sulfur;
• and
• (b) a catalytically active compound chemically bonded to the water-soluble carrier polymer, wherein the catalytically active compound is an enzyme, coenzyme, antigen, antibody, metal, metal complex, affinity material or an amino acid.