Antifungal proteins belong to a group of plant defense proteins, present in different plant tissues ranging from leaves, stems, roots to seeds. Upon fungal invasions, these proteins accumulate at the infection site to inhibit the growth of pathogens. Some antifungal proteins were found to have antifreeze and antiviral characteristics as well. Antifungal proteins are structurally diverse. Thaumatin-like proteins, chitinases, ribosome inactivating proteins, defensins, cyclophilin-like proteins and miraculin-like proteins are members of the family of antifungal proteins. There are antifungal proteins with other structures such as cysteine protease inhibitors and peptides. Apart from plant defense, antifungal proteins have been reported to affect the growth of murine immune cells including splenocytes, macrophages and bone marrow cells, as well as leukemia cells. / In my study, five antifungal proteins were isolated from plant storage tissues that were bulbs and seeds abundant in proteins, comprising a chitinase-like antifungal proteins from black turtle beans (Phaseolus vulgaris cv. black turtle), an 8-kDa antifungal peptide from green chickpea ( Cicer arietinum cv green chickpea), two thaumatin-like proteins from two kinds of chestnut (Castanopsis chinensis and Castanea mollissima) and a 7.1-kDa antifungal peptide from the Chinese daffodil (Narcissus tazetta var. chinensis). In the majority of cases, the antifungal proteins were unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel, CM-cellulose and Mono S. They showed different antifungal potencies on various phytopathogenic fungi examined including Botrytis cinerea, Fusarium oxysporum, Mycosphaerella arachidicola and Physalospora piricola. Only the daffodil and Castanopsis antifungal proteins were active on all four fungal species. The remaining three antifungal proteins inhibit 2-3 of the 4 fungi. / The purified proteins were characterized for various biological activities such as the inhibitory activity on HIV-1 reverse transcriptase and cell-free translation in a rabbit reticulocyte system. All proteins except those from daffodil bulbs and black turtle beans exhibited HIV-1 reverse transcriptase inhibitory activity. The activity of purified proteins on the proliferation of normal and tumor cells in vitro, including murine splenocytes and leukemia L1210 cells, was also studied. Daffodil antifungal protein was the only protein found to have a stimulatory activity on mouse splenocytes and an inhibitory activity on leukemia cells. (Abstract shortened by UMI.) / Chu Kin-tak. / "June 2005." / Adviser: T. B. Ng. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3574. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 175-183). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.