Protein mobilisation and proteolytic activities in root tubers of Asphodelus aestivus

Authors : Serap KIRMIZI, Gürcan GÜLERYÜZ, Hülya ARSLAN

Pages : 302-308

Doi:10.3906/bot-1301-43

View : 24 | Download : 9

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :We studied protein mobilisation in Asphodelus aestivus Brot. insert ignore into journalissuearticles values(Liliaceae); during a 1-year period. The activities of 3 proteolytic enzymes, endopeptidase insert ignore into journalissuearticles values(EP);, leucine aminopeptidase insert ignore into journalissuearticles values(LAP);, and carboxypeptidase insert ignore into journalissuearticles values(CP);, together with soluble protein levels and total nitrogen and water content in root tubers were investigated. We found that protein mobilisation continued throughout the year. The highest levels of the 3 proteolytic enzymes were found in different months: LAP in December insert ignore into journalissuearticles values(1.19 ± 0.19 µmol pNA/g FW);, CP in February insert ignore into journalissuearticles values(14.19 ± 1.13 µmol Leu/g FW);, and EP in May insert ignore into journalissuearticles values(5.18 ± 0.12 U/h);. Activities of LAP and CP generally reached their higher levels in January-April, namely in spring, but EP activity was higher in March-May. Activities of all 3 enzymes remained at lower levels during the asphodel`s inactive life phase. The soluble protein contents were associated with the proteolytic activities. The total N contents were generally constant, but decreased in April. Our results show that the proteolytic activities in root tubers of Asphodelus aestivus continue to increase up to the start of flowering in early spring, and they can be an important nitrogen resource at the beginning of the generative development phase.
Keywords : Key words Endopeptidase, leucine aminopeptidase, carboxypeptidase, Mediterranean