Fructosamine-3-Kinase (FN3K) is an
enzyme phosphorilating
fructoselysine (FL) residues on
glycated proteins, resulting in the production of
protein-bound FL-3-phosphate. The pathological role of the non-enzymatic modification of
proteins by reducing
sugars has become increasingly evident in various types of disorders, including the
cancer. In this study, our aim was to study FN3K
enzyme activity, as well as its
mRNA in human
colorectal cancer (CRC). Thirty consecutive CRC patients undergoing surgery of the colon were enrolled in the study. FN3K enzymatic activity and gene expression were analyzed using a radiometric assay and quantitative RT-PCR, respectively. FN3K is a functionally active
enzyme in human colon tissue, without significant differences between normal mucosa and
cancer. The mean level of FN3K
mRNA was significantly lower in
cancer than in the corresponding normal colorectal mucosa The
colorectal tumors located on the left side showed lower levels of both enzymatic activity and
mRNA FN3K than
tumors located in the right side of colon. This paper is the first studying FN3K
enzyme activity in human CRC, showing a significant relationship between enzymatic activity, its
mRNA and
tumor side.