The Extraction Of Sucrose-metabolizing Enzyme And Study On Correlation Of Enzyme Activities And Sugar Accumulation During Muskmelon (Cucumis Melon L.) Fruits

In this experment, enzymes (acid invertase, neutral invertase, sucrose phosphate synthase and sucrose synthase) activities were compared in extracting solution of sucrose-metabolizing enzymes which were gotten by desugaring and desalting in the muskmelon; correlation between sugar accumulation and sucrose-metabolizing enzymes and starch conversion were analyzed and discussed. The details and results are as follows: 1.Extracting solution of sucrose-metabolizing enzymes (acid invertase, neutral invertase, sucrose phosphate synthase and sucrose synthase) in the intraday anthesis muskmelon fruits of Luhoutian 1 was treated with two methods by column Sephadex G-25: one was directly desugaring; the other was deposited by (NH4)SO4, then the deposition was redissloved and resalted. Activities of sucrose-metabolizing enzymes were mensurated and their types were analyzed by SDS-PAGE (PolyAcylamine Gel Electrophoresis). The results indicated that: activities of AI and NI by desalting were higher than that by desugaring , and differences of them were extremely significant; activities of SPS and SS changed insignificantly between two extracting methods. The trial showed that: desalting method of enzymes was more excellent than desugaring method. 2.The desalting was to extracted extracting solution of sucrose-metabolizing enzyme The content of sucrose, glucose, fructose, starch and the activities of sucrose-metabolizing enzymes——acid invertase, neutral invertase, sucrose synthase and sucrose phosphate synthase——were investigated in sarcocarp of Elizabeth and Wuyin No 1. Physiological mechanism of sugar accumulation in muskmelon fruits was systemically analyzed. The result showed: sugar accumulation was very slow in Elizabeth and Wuyin No1 fruits before ripe stage, especially for sucrose. Sucrose accumulated sharply during ripe stage, while the content of fructose and glucose reduced slightly. Accumulation and components of sugars were affected evidently by AI,NI and SPS in muskmelon fruits, but the action of SS was weak. Otherwise, there was no obvious correlation between sugar accumulation and starch conversion.