PDF(Pubmed)
Abstract：
Phaseolus vulgaris α-amylase inhibitor (α-AI) is a protein that has recently gained commercial interest, as it inhibits mammalian α-amylase activity, reducing the absorption of dietary carbohydrates. Numerous studies have reported the efficacy of preparations based on this protein on the control of glycaemic peaks in type-2 diabetes patients and in overweight subjects. A positive influence on microbiota regulation has also been described. In this work, ten insufficiently studied Italian P. vulgaris cultivars were screened for α-amylase- and α-glucosidase-inhibiting activity, as well as for the absence of antinutritional compounds, such as phytohemagglutinin (PHA). All the cultivars presented α-glucosidase-inhibitor activity, while α-AI was missing in two of them. Only the Nieddone cultivar (ACC177) had no haemagglutination activity. In addition, the partial nucleotide sequence of the α-AI gene was identified with the degenerate hybrid oligonucleotide primer (CODEHOP) strategy to identify genetic variability, possibly linked to functional α-AI differences, expression of the α-AI gene, and phylogenetic relationships. Molecular studies showed that α-AI was expressed in all the cultivars, and a close similarity between the Pisu Grogu and Fasolu cultivars\' α-AI and α-AI-4 isoform emerged from the comparison of the partially reconstructed primary structures. Moreover, mechanistic models revealed the interaction network that connects α-AI with the α-amylase enzyme characterized by two interaction hotspots (Asp38 and Tyr186), providing some insights for the analysis of the α-AI primary structure from the different cultivars, particularly regarding the structure-activity relationship. This study can broaden the knowledge about this class of proteins, fuelling the valorisation of Italian agronomic biodiversity through the development of commercial preparations from legume cultivars.
摘要：
菜豆α-淀粉酶抑制剂（α-AI）是一种最近获得商业利益的蛋白质，因为它抑制哺乳动物α-淀粉酶的活性，减少膳食碳水化合物的吸收。许多研究已经报道了基于该蛋白质的制剂在2型糖尿病患者和超重受试者中控制血糖峰值的功效。还描述了对微生物群调节的积极影响。在这项工作中,筛选了十个未充分研究的意大利普通P.vulgaris品种的α-淀粉酶和α-葡萄糖苷酶抑制活性，以及缺乏抗营养化合物，例如植物血凝素(PHA)。所有品种均具有α-葡萄糖苷酶抑制剂活性，而其中两个缺少α-AI。只有Nieddone品种（ACC177）没有血凝活性。此外,用简并杂交寡核苷酸引物（CODEHOP）策略鉴定α-AI基因的部分核苷酸序列，以鉴定遗传变异性，可能与功能性α-AI差异有关，α-AI基因的表达，和系统发育关系。分子研究表明，α-AI在所有品种中都有表达，通过比较部分重建的一级结构，发现了PisuGrogu和Fasolu品种\'α-AI和α-AI-4同工型之间的相似性。此外，机械模型揭示了连接α-AI与α-淀粉酶的相互作用网络，其特征在于两个相互作用热点(Asp38和Tyr186)，为分析不同品种的α-AI初级结构提供了一些见解，特别是关于结构-活动关系。这项研究可以拓宽对这类蛋白质的认识，通过开发豆类品种的商业制剂，促进了意大利农艺生物多样性的价值。
