Dolichos biflorus agglutinin (DBA) is one of the well known plant lectins that are widely used in clinical serology to differentiate human blood group A₁ and A₂ erythrocytes and also applied to glycobiology. However, the knowledge of recognition factors of polyvalent (super) glycotopes in glycans and the roles of functional group and epimer in monosaccharide (sub-monosaccharide recognition factor) have not been well established. The size and shape of the recognition (combining) site of DBA has not been clearly defined. In this study, many importnat recognition factors of DBA-glycan binding were characterized by our established enzyme-linked lectinosorbent (ELLSA) and inhibition assays. The results of these assays showed that the intensity profile of the recognition factors for the major combining site of DBA was expressed by Mass relative potency (Mass R.P.) and shown by decreasing order of high density of polyvalent GalNAcα1 → (super glycotopes, 3.7 × 10³) >> the corresponding β anomers >> monomeric GalNAcα1 → related glycotopes (GalNAc as 1.0) >> their GalNAc β-anomers >> Gal (absence of NHCH₃CO at carbon-2 of GAlNAc) and GlcNAc (different epimer of Carbon-4 in GalNAc). From the all data available, it is proposed that the combining site of DBA should consist of a small cavity shape as major site and most complementary to monomeric GalNAcα → located at both terminal reducing end (Tn) and nonreducing end of glycan chains, and with a wide and broad area as subsite to accomodate from mono- to tetra-saccharides (GalNAcβ, Galβ1 → 3/4GlcNAc, lFuc1 → 2Galβ1 → 3/4GlcNAc, GalNAcβ1 → 3Galα1 → 4Galβ1 → 4Glc) at the nonreducing side. In this study, it has provided the most (comprehensive) recognition knowledge of DBA-glycan interactions at the factors of glycotope, super glycotope/sub-monosaccharide levels. Thus, it should expand and upgrade the conventional concept of the combining (recognition) site of DBA since 1980s.

双花豆凝集素 (DBA) 是一种众所周知的植物凝集素，广泛应用于临床血清学中区分人血型A ₁和A ₂红细胞，也应用于糖生物学。然而，对于聚糖中多价（超）糖表位的识别因子以及单糖（亚单糖识别因子）中官能团和差向异构体的作用的认识尚未充分建立。DBA识别（结合）位点的大小和形状尚未明确定义。在本研究中，DBA-聚糖结合的许多重要识别因子通过我们建立的酶联凝集素吸附剂 (ELLSA) 和抑制测定进行了表征。这些测定的结果表明，DBA主要结合位点的识别因子的强度分布由质量相对效力（Mass RP）表示，并通过多价 GalNAcα1 →（超级糖表位，3.7 × 10 ³ ) >> 相应的 β 端基异构体 >> 单体 GalNAcα1 → 相关糖表位 (GalNAc 作为 1.0) >> 它们的 GalNAc β-端基异构体 >> Gal（GAlNAc的碳 2 处不存在 NHCH ₃ CO）和 GlcNAc（碳的不同差向异构体） -4（在 GalNAc 中））。根据所有可用数据，建议 DBA 的结合位点应由一个小空腔形状作为主要位点组成，并且与单体 GalNAcα 最互补 → 位于聚糖链的末端还原端 (Tn) 和非还原端，并且在非还原侧有一个广泛而广泛的区域作为子位点，可容纳从单糖到四糖（GalNAcβ，Galβ1→3/4GlcNAc，lFuc1→2Galβ1→3/4GlcNAc，GalNAcβ1→3Galα1→4Galβ1→4Glc）。在这项研究中，它在糖表位、超糖表位/亚单糖水平上提供了最（全面）的 DBA-聚糖相互作用的识别知识。因此，它应该扩展和升级自20世纪80年代以来DBA结合（识别）站点的传统概念。