Gian Luca Marongiu successfully defended his Master thesis: “In silico and in vitro subsite preferences of human chitinolytic enzymes”.

Today, Gian Luca Marongiu successfully defended his Master thesis on a detailed characterisation of human chitinolytic enzymes, supported by Prof. Bruno Moerschbacher, and by Prof. Dirk Prüfer from our institute. She had been supervised by our doctoral candidate Margareta Hellmann, together with Dr. Stefan Cord-Landwehr. Humans possess three chitinolytic enzymes: two true chitinases, namely chitotriosidase and acidic mammalian chitinase, and lysozyme. Luca characterised the first two, which were provided as homologously over-expressed recombinant enzymes by Dr. Christian Gorzelanny from the Eppendorf University Hospital in Hamburg. While waiting for the enzymes, he performed an in depth in silico analysis of one of the enzymes, chitotriosidase, and its interactions with different, fully and partially acetylated substrates. These were then complemented by very detailed biochemical analyses which unexpectedly, revealed that the two enzymes are surprisingly similar, almost identical, in their mode of action and in their products. Together with the equally detailed analysis of lysozyme which Margareta will perform (because the commercial recombinant enzyme we had first used turned out to be contaminated by a chitinase, and the recombinant enzyme from Christian did not arrive in time for Luca’s thesis), this will contribute to the most advanced publication to date on the human chitinolytic enzymes, especially concerning their action on chitosans rather than on chitin. This is important, as chitosans applied to human tissues, e.g. as wound dressings or as drug-delivering nanoparticles, will be subject to processing by these enzymes, potentially influencing their bioactivities or cellular targeting, as well as their metabolic fate.