How was Sidney Altman awarded the Nobel Prize?

Name: Sidney Altman. 
Country: Canada, United States.
Date of Birth: 7 May 1939.
Died: April 5, 2022.
The subject of Study: RNA Catalysis Ribonucleoprotein.
Noble Prize Year: Nobel Prize for Chemistry in 1989 for their discoveries concerning the catalytic properties of RNA, or ribonucleic acid.