Two thermostable isoforms of a hexosaminidase were purified to homogeneity from the soluble extract of freshwater mussel Lamellidens corrianus, employing a variety of chromatographic techniques. Hexosaminidase A (HexA) is a heterodimer with subunit masses of ~80 and 55 kDa. Hexosaminidase B (HexB) is a homodimer with a subunit mass of 55–60 kDa. Circular dichroism spectroscopic studies indicated that both HexA and HexB contain β-sheet as the major secondary structural component with considerably lower content of α-helix. The temperature and pH optima of both the isoforms were found to be 60 °C and 4.0, respectively. The IC₅₀ values for HexA with N-acetyl-d-galactosamine, N-acetyl-d-glucosamine, d-galactosamine, d-glucosamine, methyl α-d-mannopyranoside and d-mannose are 3.7, 72.8, 307, 216, 244 and 128 mM, respectively, whereas the corresponding IC₅₀ values for HexB were estimated as 5.1, 61, 68, 190, 92 and 133 mM, respectively. Kinetic parameters K_M and V_max for HexA and B with p-nitrophenyl N-acetyl-β-d-glucosaminide are 4 mM, 0.23 μmol·min⁻¹·mL⁻¹ and 2.86 mM, 0.29 μmol·min⁻¹·mL⁻¹, respectively, and with p-nitrophenyl N-acetyl-β-d-galactosaminide are 4.5 mM, 0.054 μmol·min⁻¹·mL⁻¹ and 1.4 mM, 0.14 μmol·min⁻¹·mL⁻¹, respectively. GalNAc inhibited both isoforms in a non-competitive manner, whereas a mixed mode of inhibition was observed with GlcNAc with both forms.

使用多种色谱技术，从淡水贻贝Lamellidens corrianus的可溶性提取物中纯化了己糖胺酶的两种热稳定亚型。己糖胺酶A（HexA）是异源二聚体，亚基质量约为80和55 kDa。己糖胺酶B（HexB）是同型二聚体，亚单位质量为55–60 kDa。圆二色性光谱研究表明，HexA和HexB都含有β-片层作为主要的次要结构成分，而α-螺旋的含量却低得多。两种同工型的最适温度和最适pH分别为60°C和4.0。该IC ₅₀与值HexA的Ñ乙酰基d -galactosamine，Ñ乙酰基d-葡萄糖胺，d-半乳糖胺，d-葡萄糖胺，甲基α- d-甘露吡喃糖苷和d-甘露糖分别为3.7、72.8、307、216、244和128 mM，而HexB的相应IC ₅₀值估计为5.1， 61、68、190、92和133 mM。HexA和B与对-硝基苯基N-乙酰基-β - d-氨基葡萄糖的动力学参数K _M和V _max为4 mM，0.23μmol·min ^-1 ·mL ^-1和2.86 mM，0.29μmol·min ^-1 ·mL ^-1，分别与对硝基苯基N-乙酰基-β- d-半乳糖胺分别为4.5 mM，0.054μmol·min ^-1 ·mL ^-1和1.4 mM，0.14μmol·min ^-1 ·mL ^-1。GalNAc以非竞争性方式抑制两种同工型，而在两种形式的GlcNAc中观察到混合的抑制方式。