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Heterogeneous mixtures of collagen fragments can be used as nutrition supplement or as key ingredients for ointments with therapeutic relevance in wound healing. Some mixtures of collagen fragments are referred to as collagen hydrolysates owing to the production process with hydrolytic enzymes. Since the precise composition of collagen hydrolysates is generally unknown, it is of interest to analyze samples containing various collagen fragments with appropriate biophysical methods. Any product optimization without a profound knowledge concerning the size and the molecular weight distribution of its components is nearly impossible. It turned out that a combination of AFM methods with NMR techniques is exceptionally suited to examine the size range and the aggregation behavior of the collagen fragments in the hydrolysates of fish, jellyfish, chicken, porcine and bovine collagen. Supported by molecular modeling calculations, the AFM and NMR experiments provide a detailed knowledge about the composition of collagen hydrolysates and collagen ointments. Furthermore, the data allow a correlation between the size of the fragments and their potential bioactivity.

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Tyrosinase catalyzes the conversion of tyrosine to dihydroxyphenylalanine quinone, which is the main precursor for the biosynthesis of melanin. The enzyme from Agaricus bisporus, the common button mushroom, was purified and crystallized in two different space groups. Crystals belonging to space group P2 1 (unit-cell parameters a = 104.2, b = 105.0, c = 119.1 Å , = 110.6, four molecules per asymmetric unit) diffracted to 3.0 Å resolution. Crystals belonging to space group P2 1 2 1 2 (unit-cell parameters a = 104.0, b = 104.5, c = 108.4 Å , two molecules per asymmetric unit) diffracted to 2.6 Å resolution. It was essential to include 5 mM HoCl 3 in all crystallization conditions in order to obtain well diffracting crystals.

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