Proteolytic enzymes from generative organs of flowering plants (Angiospermae)

Pollen proteases were discovered over 100 years ago, whereas the enzymes from female tissues have been used since the Roman era in simple biotechnological processes. In the last decade a great progress has been made in studies on plant proteases, including those from the generative organs. This paper reviews reports published in the last decade, concerning purification, properties and localization of proteases from generative parts of flowering plants against the background of the general proteolytic machinery of the plant. Special attention is paid to differences in protease structure and properties in comparison to other enzymes from the same catalytic classes. Participation of the proteases in all steps of pollen-pistil interaction as well as in pollen tube growth is discussed. Further intensive studies with use of native substrates are necessary to understand the role of proteases in pollination.