Over the past 18 years we have been deeply involved with the synthesis and applications of stimuli-responsive polymer systems, especially polymer-biomolecule conjugates. This article summarizes our work with one of these conjugate systems, specifically polymer-protein conjugates. We include conjugates prepared by random polymer conjugation to lysine amino groups, and also those prepared by site-specific conjugation of the polymer to specific amino acid sites that are genetically engineered into the known amino acid sequence of the protein. We describe the preparation and properties of thermally sensitive random conjugates to enzymes and several affinity recognition proteins. We have also prepared site-specific conjugates to streptavidin with temperature-sensitive polymers, pH-sensitive polymers, and light-sensitive polymers. The preparation of these conjugates and their many fascinating applications are reviewed in this article.

Over the past 18 years we have been deeply involved with the synthesis and applications of stimuliresponsive polymer systems, especially polymerbiomolecule conjugates. This article summarizes our work with one of these conjugate systems, specifically polymerprotein conjugates. We include conjugates prepared by random polymer conjugation to lysine amino groups, and also those prepared by site-specific conjugation of the polymer to specific amino acid sites that are genetically engineered into the known amino acid sequence of the protein. We describe the preparation and properties of thermally sensitive random conjugates to enzymes and several affinity recognition proteins. We have also prepared site-specific conjugates to streptavidin with temperature-sensitive polymers, pHsensitive polymers, and light-sensitive polymers. The preparation of these conjugates and their many fascinating applications are reviewed in this article.

A series of hydrogels with large pores was synthesized by the precipitation polymerization of 2-hydroxyethyl methacrylate (HEMA) with crosslinking agent in aqueous solution. Such gels are potentially useful for the controlled release of large-molecular-weight species such as proteins. In this study, the release behavior of lysozyme and alpha-amylase from hydrogels formed from HEMA or HEMA with a comonomer was studied. It was found that the polymer composition affected the total amount of lysozyme released and its activity. Effects were smaller with alpha-amylase. Charged gels, containing a phosphate moiety, released larger amounts of lysozyme at a reduced rate as a result of charge-charge interactions.

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Polyamine macromonomer possessing a polymerizable vinyl group at the chain end was synthesized by lithium amide catalyzed anionic self-polyaddition reaction of N,N'-diethyl-N-(4-vinylphenethyl)ethylenediamine. To elucidate the reaction mechanism for the macromonomer synthesis, the quantitative analyses were carried out on this reaction using double-wavelength UV method as well as UV fourth order derivative spectra method. The number average-molecular weight of the macromonomer was also measured with these UV methods. From these studies, it was concluded that one to one complex consisting of > NH and > NLi played an important role in the successive addition reactions. When the ratio of [>NH] to [ > NLi] became smaller to approach unity, there occurred a break point at which the rate of the addition reaction decreased sharply. The number average molecular weight of the macromonomer at the point was expressed by a simple equation (cf eq 7). Thus, it was possible to control the molecular weight of the polyamine macromonomer by adjusting the relative concentrations of > NH to > NLi in the initial mixture for the polyaddition reaction.