Isolation, purification and some properties of L-lysine α-oxidase from trichoderma SP. 6

The variety of oncological diseases triggers the elaboration of new anti tumor drugs. Considerable achievements in human cancer therapy were based on the different sensitivity of normal and tumor tissues to the lack of the essential growth factors. This fact caused the search for the new enzymes effecting some metabolic reactions essential for the growing cancer cells. The first enzyme, which was used in oncology, was L-asparaginase [1]. The preparations of this enzyme from various sources differed in their properties, so that their immunological reactivity did not intersept. L-asparaginases were effective for the treatment of lymphoid tumors, but did not show activity against other types of tumors. Several other enzymes were investigated as the potential anti cancer agents, but presently they do not play a significant role in tumor therapy [2]. It is well known that L-lysine is essential for human organism because there are no reactions for its biosynthesis, so food is the only source of this amino acid. L-Lysine is very important for biochemical processes. It stabilizes deoxy hemoglobin; the DNA-binding proteins of chromatin are rich with lysine as well as the proteins of connective tissues. Tumor cells are more sensitive to the lack of essential growth factors in comparison with the normal cells. The depletion of L-lysine causes inhibition of tumor cells growth. One of the enzymes destroying L-lysine is L-lysine alpha-oxidase (1.4.3.14) (LO), which was isolated for the first time in Japan [3] from the Trichoderma viride Y-244-2 grown on soaked wheat bran. Later LO was isolated in Russia from the strain Trichoderma harzianum Rifai [4]. For the purposes of practical oncology it is very important to have the enzymes, which catalyse the same reaction, but differ in their immunological reactivity. This aim could be achieved by using different sources of enzyme. The aim of the present work was to find new strains-producers of LO, capable of intensive enzyme biosynthesis in the bioreactors, and to investigate LO from the new strain with the purpose of its practical application in oncology. © 2012 Nova Science Publishers, Inc. All rights reserved.