HEXB/Hexosaminidase B Protein, Human (HEK293, His)

HEXB (Hexosaminidase B) protein exhibits hydrolytic activity towards the non-reducing end N-acetyl-D-hexosamine and/or sulfated N-acetyl-D-hexosamine residues found in various glycoconjugates, including oligosaccharide moieties from proteins, neutral glycolipids, and specific mucopolysaccharides. Notably, the B isozyme demonstrates efficient hydrolysis of neutral oligosaccharides, distinguishing it from other substrates. While isozyme A is responsible for the degradation of GM2 gangliosides in the presence of GM2A, isozyme B does not participate in this process. During fertilization, HEXB, specifically isozyme B, plays a crucial role in the zona block to polyspermy. It is localized in the cortical granules of non-activated oocytes and is exocytosed during the cortical reaction triggered by oocyte activation. This exocytosis results in the inactivation of the sperm galactosyltransferase-binding site, contributing to the prevention of sperm binding to the zona pellucida and ensuring the integrity of the zona block to polyspermy.