Nitrile hydratase of Rhodococcus sp. N-774. Purification and amino acid sequences

The nitrile hydratase of Rhodococcus sp. N-774 was purified and crystallized. The enzyme is composed of two different subunits (molecular masses: subunit alpha, 28,500 Da; subunit beta, 29,000 Da). The amino-terminal amino acid sequence of each subunit was determined. There is no sequence homology between the two subunits, suggesting that the peptides originate from different cistrons. The activity of the purified enzyme did not decrease during incubation in the dark, whereas it gradually decreased in intact cells.