Biofunctional membranes Part IV. Active-site structure and stability of an immobilized enzyme, papain, on modified polysulfone membranes studied by electron paramagnetic resonance and kinetics

A new formulated stable papin-pectin aerosol spray for skin wound healing

“…This is not seen for the papain in solution which may suggest that papain immobilized in pectin gel has better stability at lower pressures. The enhancement in thermal stability of immobilized papain has also been reported in many other enzyme immobilization studies [15,21,22] in which the authors explained that the higher stability of immobilized papain (around the 30 min of incubation) could be due to the diminished autolysis of the enzyme trapped into the support. Also it may be related to the rigidity of the conformation of the enzyme molecules resulting from its distribution on the gel matrix as well as from interaction between enzyme and pectin molecules.…”

“…N 2 propellant is, therefore, preferred over air because it has no capacity to oxidize the thiolate ion at the active site of papain to adversely affect its enzyme activity. Furthermore, other researchers [15,21,22] have reported that papain immobilized in different supports could provide more thermal stability due to diminished autolysis of the enzyme trapped in the supporting material. Additionally, the rigidity of the conformation of papain molecules from their distribution in the gel matrix as well as from the strong interaction between papain and pectin molecules could possibly contribute to its higher thermal stability in the pectin gel.…”

Kinetics and Active Fraction Determination of a Protease Enzyme Immobilized on Functionalized Membranes: Mathematical Modeling and Experimental Results

“…The enzyme undergoes conformational changes as a result of immobilization which directly influence its catalytic activity (Butterfield et al, 1994; Bhardwaj et al, 1996). It could also deactivate with time and by leaching and eluting out of the support matrix (Shyam et al, 1975; Houng et al, 1993; Rialdi and Battistel, 1996).…”

“…To better understand the properties and functional response of the immobilized protein it is necessary to study these changes. Electron paramagnetic spectroscopy (EPR) is a powerful tool that is widely used in several areas of study including biological systems, polymer chemistry, and free radical reactions and also to study fouling in ultrafiltration membranes (Butterfield et al, 1994a; Friedrich et al, 1980; Oppenheim et al, 1994). EPR requires the presence of a paramagnetic molecule (Butterfield, 1982).…”

“…The percentages of the two subpopulations in different samples of the immobilized enzyme were delineated, assuming that the enzyme existed in the same two states in all samples, only differing in relative amounts of the two populations. Since this EPR investigation, the technique has been used to study changes in conformation of different kinds of immobilized enzymes, including alcohol dehydrogenase, β‐galactosidase, subtilisin, papain, and glutamate dehydrogenase (Marg et al, 1986; Skerker and Clark, 1987; Clark et al, 1987, 1988; Telo et al, 1990; Zhuang and Butterfield, 1992; Butterfield et al, 1994; Ganapathi et al, 1995; Bhardwaj et al, 1996; O'Connor and Bailey, 1989; Viswanath et al, 1998). In most EPR reports of enzymes on supports, two subpopulations have been discerned, but just one population and as many as three subpopulations have also been observed (Zhuang and Butterfield, 1992; Song et al, 1992).…”