Activities of serine hydroxymethyltransferase in murine tissues and tumours

The specific activity of the enzyme serine hydroxymethyltransferase (EC 2.1.2.1) was determined in various murine, rat and human tumour cell lines. The activities of the enzyme were also investigated in tissues of non-tumour bearing DBA/2 mice and BALB/c mice bearing the PC6 ascites tumour. The highest enzyme activity in the murine tissues was found in the liver and then the kidneys. The enzyme was present in all the tissues assayed. The activities of enzyme found in the tumours varied considerably, with the PC6 ascites, Walker 256 and Lewis lung cells, being the highest.