SPINACH CHLOROPLAST ATP-DEPENDENT ENDOPEPTIDASE TI-LIKE PROTEASE

The soluble fraction of spinach chloroplast was used for purification and characterization of an ATP-dependent protease. Purification includ ed Q Sepharose Fast Flow, hydroxylapatite and FPLC Superose 6 column c hromatography. The isolated enzyme requires ATP and Mg2+ for stimulati on and represents a ubiquitin independent serine protease, containing essential sulphydryl group(s). By using fluorogenic peptides a similar ity of chloroplast protease to Escherichia coli Ti protease was observ ed. The chloroplast protease is immunochemically cross - reactive with the bacterial protease Ti.