Purification and characterization of an enzyme from a strain ofOchrobactrum anthropithat degrades condensation products of urea and formaldehyde (ureaform)

An enzyme hydrolyzing the condensation products of urea and formaldehyde (ureaform) was purified and characterized from a bacterium isolated from soil and described as Ochrobactrum anthropi UF4. The enzyme designated as methylenediurea amidinohydrolase (methylenediurea deiminase) hydrolyzed ureaform condensation products of different length (methylenediurea, dimethylenetriurea, trimethylenetetraurea) to ammonium, formaldehyde, and urea at molar ratios of 2:1:1 (methylenediurea), 4:2:1 (dimethylenetriurea), and 6:3:1 (trimethylenetetraurea). Two other substrates, ureidoglycolate and allantoate, were also hydrolyzed, yielding glyoxylate and urea (ureidoglycolate) and glyoxylate, urea, and ammonium (allantoate), respectively. The molecular mass of the enzyme was determined by size exclusion chromatography to be 140 ± 25 kDa; the enzyme was composed of identical subunits of 38 ± 5 kDa, indicating that the native enzyme has a tetrameric structure. Growth of the bacterium in the presence of ureaform specifically induced the methylenediurea deiminase and no complete repression of enzyme synthesis by ammonium was observed.Key words: ureaformaldehyde, methylenediurea deiminase, fertilizer, Ochrobactrum anthropi.