American Society of Hirudotherapy

Structure and cleavage pattern of a hyaluronate 3-glycanohydrolase in the glycoside hydrolase 79 family

Crystal structure paper published in Carbohydrate Polymers (2021)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsDrug DevelopmentHuang H et al. · Carbohydrate Polymers, 2021

Abstract

Hyaluronidases have attracted a great deal of interest in the field of medicine due to their fundamental roles in the breakdown of hyaluronan. However, little is known about the catalytic mechanism of the hyaluronate 3-glycanohydrolases. Here, we report the crystal structure and cleavage pattern of a leech hyaluronidase (LHyal), which hydrolyzes the β-1,3-glycosidic bonds of hyaluronan. LHyal exhibits the typical structural features of glycoside hydrolase 79 family but contains a variable 'exo-pocket' loop where basic residues R102 and K103 are the structural determinants of hyaluronan binding. Through analysis of the hydrolysis of even- and odd-numbered hyaluronan oligosaccharides, we demonstrate that hexasaccharide is the shortest natural substrate, which can be cleaved from both the reducing and non-reducing ends to release disaccharides, and pentasaccharides are the smallest fragments for recognition and hydrolysis. These observations provide new insights into the degradation of hyaluronan and the evolutionary relationships of the GH79 family enzymes.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article
Indexed MeSH termsAnimalsHyaluronic AcidHyaluronoglucosaminidaseHydrolysisLeechesModels, Molecular

Summary

Crystal structure and cleavage pattern of leech hyaluronidase (LHyal), which hydrolyzes beta-1,3-glycosidic bonds of hyaluronan — establishing residues R102 and K103 as substrate-binding determinants in the GH79 family.

Why This Matters for Hirudotherapy

This study reports the crystal structure and cleavage pattern of a leech hyaluronidase (LHyal), an enzyme in glycoside hydrolase family 79 that hydrolyzes β-1,3-glycosidic bonds of hyaluronan. The authors identified key structural determinants of hyaluronan binding (residues R102 and K103) and characterized minimum substrate sizes for recognition and hydrolysis, showing hexasaccharide as the shortest natural substrate. This work is relevant to understanding leech-produced enzymes and their biochemical roles. However, this is a structural/biochemical study with no therapeutic, pharmacological, or clinical data, and no direct connection to hirudotherapy practice is established.

Citation

Structure and cleavage pattern of a hyaluronate 3-glycanohydrolase in the glycoside hydrolase 79 family.

Huang H et al. · Carbohydrate Polymers, 2021

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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