Hyaluronidase activity of human Hyal1 requires active site acidic and tyrosine residues.

ABSTRACT: Hyaluronidases are a family of endolytic glycoside hydrolases that cleave the beta1-4 linkage between N-acetylglucosamine and glucuronic acid in hyaluronan polymers via a substrate-assisted mechanism. In humans, turnover of hyaluronan by this enzyme family is critical for normal extracellular matrix remodeling. However, elevated expression of the Hyal1 isozyme accelerates tumor growth and metastatic progression. In this study, we used structural information, site-directed mutagenesis, and steady state enzyme kinetics to probe molecular determinants of human Hyal1 function. Mutagenesis of active site residues Glu(131) and Tyr(247) to Gln and Phe, respectively, eliminated activity at all hyaluronan concentrations (to 125 microm or 2.5 mg/ml). Conservative mutagenesis of Asp(129) and Tyr(202)

SUBMITTER: Zhang L 

PROVIDER: S-EPMC2666596 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature