The present invention provides pharmaceutical preparations for anti-inflammation, anti-infection, inhibition of cancer metastasis etc., foods such as dairy products etc., and a method for improving proteins, as well as a method for diagnosis of inflammatory diseases and cancer malignancy. According to the present invention, there can be provided a polypeptide having poly-N-acetyllactosamine sugar chains synthesis-related activity, a process for producing the polypeptide, DNA coding for the polypeptide, a process for producing the DNA, a recombinant vector having the DNA integrated therein, a transformant carrying the recombinant vector, an antibody recognizing the polypeptide, a process for producing poly-N-acetyllactosamine sugar chains by use of the DNA or the polypeptide, diagnosis and treatment of diseases such as inflammations, cancers etc. by use of the DNA, the polypeptide or the antibody, determination and immunostaining of the polypeptide of the present invention by use of the antibody, a method for screening a compound varying the expression of a gene coding for the polypeptide, and a method for screening a substance varying the activity of the polypeptide.