Abstract: For a deep study on the characters of starch phosphorylase(SP) as well as its physiological effects during starch metabolism, the optimum extractive techniques and measurement conditions of SP in the bulb of Lilium davidii var. unicolor were ascertained, furthermore, some biochemical nature of this enzyme were preliminarily studied in this experiment. The results indicated that the best extractive buffer was succinic acid solution with pH 5.8. The optimal reaction system comprised 25 mmol·L^-1 Glc-1-P as substrate, and incubating for 10 min at 30℃. Within the pH scale from 5 to 6, SP presented higher activity. However, SP in lily bulb couldn’t be reserved for a long time and couldn’t sustain higher temperature. Stored for 12 hours at 4℃, SP activity only remained 50%, and almost lost completely after incubating for 30 min at 40℃.

Key words: Lilium davidii var. unicolor, starch phosphorylase(SP), extractive condition, measurement condition