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。