Abstract
Abstract Papaya lysozyme, purified by ion exchange chromatography on IRC-50, has been investigated with respect to physicochemical and enzymatic properties. In agreement with earlier findings, it was found that papaya lysozyme has a molecular weight of about 25,000 and that glycine is its sole amino-terminal residue. Molecular weight determinations in dissociating solvents indicate that the molecule consists of a single polypeptide chain. Papaya lysozyme lyses Micrococcus lysodeikticus cell walls at a rate one-third of that exhibited by egg white lysozyme; however, it displays a chitinase activity toward tetra-N-acetyl-d-glucosamine 400 times that of the egg white enzyme. No involvement of tryptophan residues in the active site of papaya lysozyme could be demonstrated.
Highlights
This paper presents a comparison of the physicochemical and enzymatic properties of such preparations with those of egg white lysozyme
Rechromatography of the most retarded component indicated a single symmetrical peak with an elution volume identical with that obtained on the original chromatographic separation
Since papaya lysozyme is extracted from the latex together with a number of proteolytic enzymes, notably the sulfhydryl proteases papain and chymopapain [3]) the crystalline enzyme as well as the various lysozyme components obtained by ion exchange chromatography were examined for the presence of
Summary
Papaya lysozyme, purified by ion exchange chromatography on IRC-50, has been investigated with respect to physicochemical and enzymatic properties. In 1955, Smith et al [3] reported the isolation and characterization of a crystalline lysozyme from papaya latex This protein showed powerful lytic activity toward suspensions of Sarcina lutea [3]. The molecular weight of papaya lysozyme, 25,000, was strikingly different from that of lysozymes from animal sources [3]. The latter enzymes all have molecular weights of about 14,000 [4]. Lysozymes from animal sources and egg white lysozyme, in particular, have been extensively studied in recent years [4]. In contrast to egg white lysozyme, no involvement of tryptophan in the active site of papaya lysozyme could be demonstrated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
