Abstract: Compounds containing carbohydrate moieties or carboxyl groups are linked to either compounds containing thiol moieties or electron-deficient moieties by the use of linking agents of the formula ##STR1## in which R.sup.1 is NH.sub.2 -- or NH.sub.2 --NH--; R.sup.2 is --NH--C(O)--, --C(O)--NH--, or --C(O)--; R.sup.3 is C.sub.1 -C.sub.10 alkylene, C.sub.5 -C.sub.7 cyclic alkylene, arylene, phenyl-substituted C.sub.1 -C.sub.10 alkylene, benzyl-substituted C.sub.1 -C.sub.10 alkylene, or amino-substituted C.sub.1 -C.sub.10 alkylene; R.sup.4 is H, acetyl, ##STR2## where R.sup.5 is C.sub.1 -C.sub.5 alkyl; m is zero or 1; and n ia zero or 1.

Abstract: Macromolecular species such as enzymes, proteins, drugs, and solid supports which contain reactive carbonyl, groups or groups which are readily converted to reactive carbonyl groups are modified by reaction with a compound of the formula ##STR1## in which R.sup.1 is H, C.sub.1 -C.sub.20 alkyl, phenyl, (C.sub.1 -C.sub.10 alkyl)-substituted phenyl, or phenyl-substituted C.sub.1 -C.sub.10 alkyl; R.sup.2 is C.sub.2 -C.sub.5 alkylene or (C.sub.1 -C.sub.4 alkoxy)-substituted C.sub.2 -C.sub.5 alkylene; R.sup.3 is ##STR2## R.sup.4 is H or C.sub.1 -C.sub.4 alkyl; n is at least 5; and m is zero or 1.

Abstract: Macromolecular species such as enzymes, proteins, drugs, and solid supports which contain reactive carbonyl groups or groups which are readily converted to reactive carbonyl groups are modified by reaction with a compound of the formula ##STR1## in which R.sup.1 is H, C.sub.1 -C.sub.20 alkyl, phenyl, (C.sub.1 -C.sub.10 alkyl)-substituted phenyl, or phenyl-substituted C.sub.1 -C.sub.10 alkyl; R.sup.2 is C.sub.2 -C.sub.5 alkylene or (C.sub.1 -C.sub.4 alkoxy)-substituted C.sub.2 -C.sub.5 alkylene; R.sup.3 is ##STR2## R.sup.4 is H or C.sub.1 -C.sub.4 alkyl; n is at least 5; and m is zero or 1.

Abstract: Macromolecular species such as enzymes, proteins, drugs, and solid supports which contain reactive carbonyl groups or groups which are readily converted to reactive carbonyl groups are modified by reaction with a compound of the formula ##STR1## in which R.sup.1 is H, C.sub.1 -C.sub.20 alkyl, phenyl, (C.sub.1 -C.sub.10 alkyl)-substituted phenyl, or phenyl-substituted C.sub.1 -C.sub.10 alkyl; R.sup.2 is C.sub.2 -C.sub.5 alkylene or (C.sub.1 -C.sub.4 alkoxy)-substituted C.sub.2 -C.sub.5 alkylene; R.sup.3 is ##STR2## R.sup.4 is H or C.sub.1 -C.sub.4 alkyl; n is at least 5; and m is zero or 1.

Abstract: Macromolecular species such as enzymes, proteins, drugs, and solid supports which contain reactive carbonyl groups or groups which are readily converted to reactive carbonyl groups are modified by reaction with a compound of the formula ##STR1## in which R.sup.1 is H, C.sub.1 -C.sub.20 alkyl, phenyl, (C.sub.1 -C.sub.10 alkyl)-substituted phenyl, or phenyl-substituted C.sub.1 -C.sub.10 alkyl; R.sup.2 is C.sub.2 -C.sub.5 alkylene or (C.sub.1 -C.sub.4 alkoxy)-substituted C.sub.2 -C.sub.5 alkylene; R.sup.3 is ##STR2## R.sup.4 is H or C.sub.1 -C.sub.4 alkyl; n is at least 5; and m is zero or 1.

Abstract: Compounds containing carbohydrate moieties or carboxyl groups are linked to either compounds containing thiol moieties or electron-deficient moieties by the use of linking agents of the formula ##STR1## in which R.sup.1 is NH.sub.2 -- or NH.sub.2 --NH--; R.sup.2 is --NH--C(O)--, --C(O)--NH--, or --C(O)--; R.sup.3 is C.sub.1 -C.sub.10 alkylene, C.sub.5 -C.sub.7 cyclic alkylene, arylene, phenyl-substituted C.sub.1 -C.sub.10 alkylene, benzyl-substituted C.sub.1 -C.sub.10 alkylene, or amino-substituted C.sub.1 -C.sub.10 alkylene; R.sup.4 is H, acetyl, ##STR2## where R.sup.5 is C.sub.1 -C.sub.5 alkyl; m is zero or 1; and n is zero or 1.