| 摘要 |
A previously unknown aspartic protease capable of cleavage of proteins by hydrolysis, referred to herein as "napsin", has been cloned from a human liver library. Two cDNA clones have been cloned, sequenced and expressed. These encode isozymes of the protease, referred to as "napsin A" and "napsin B". The gene has also be obtained and partially sequenced. A process for rapid purification of the enzyme using immobilized petpstatin has also been developed, and enzyme isolated from human kidney tissue. Polyclonal antibodies to the enzymes have been made which are also useful for isolation and detection of the enzyme. Similarities to other aspartic proteases, especially cathepsin D, establish the usefulness of the enzyme in diagnostic assays as well as as a protease. Either or both the amount or type of napsin expressed in a particular tissue can be determined using labelled antibodies or nucleotide probes to the napsin. |
