甘藷(Ipomoea batatas (L.) Lam. 'Tainong 57')塊根黏質多醣經由初抽；及進一步SDS和熱處理之純化步驟，在電泳膠片顯示達到均質。以(N-(3-[2-furyl]acryloyl)-Phe-Gly-Gly)(FAPGG)為受質，利用分光光度計的方法分析此一均質的甘藷黏質多醣抑制血管收縮素轉化酶的能力（50到400μg/mL黏質多醣，分別抑制28.7到59.8%血管收縮素轉化酶活性）其效果隨劑量增加而增加。甘藷黏質多醣對於血管收縮素轉化酶之50%抑制濃度(IC50)為364.5μg/mL，對照組captopril為10nM(8.68μg/mL)。商品化的多糖類果膠（50到400μg/mL）對於血管收縮素轉化酶並沒有類似的抑制效果。另外利用螢光 silica TLC偵測FAPGG及其水解產物FAP，結果也顯示甘藷黏質多醣對於血管收縮素轉化酶有抑制的效果。甘藷黏質多醣對於血管收縮素轉化酶是屬於混合型抑制，而Michaelis常數為12mM.
Sweet potato (Ipomoea batatas (L.) Lam. 'Tainong 57') storage root mucilage was extracted (crude mucilage) and further purified by SDS and heating treatment (purified mucilage). Purified mucilage treated with 2-mercaptoethanol moved as a single band in SDS-PAGE. This purified mucilage was active to inhibit angiotensin converting enzyme (ACE) as shown by spectrophotometric method in a dose-dependent manner (28.7 to 59.8% ACE inhibition, respectively, by 50 to 400 μg/mL mucilage) using (N-(3-[2-furyl] acryloyl)-Phe-Gly-Gly) (FAPGG) as a substrate. The concentration of mucilage required for 50% inhibition (IC50) of ACE activity was 364.5 μg/mL while that of captopril was 10 nM (8.68 μg/mL). The commercial polysaccharide pectin (50 to 400 μg/mL) showed no inhibitory activity against ACE. When using fluorescent silica TLC to detect FAPGG and FAP, the results also showed that mucilage inhibited ACE. The mucilage showed mixed type inhibition against ACE, and the Michaelis constant in the presence of mucilage was 12 mM. We suggest that consumption of sweet potato storage root mucilage may benefit people's health.
