Aspartic proteinase from barley grains is related to mammalian lysosomal cathepsin D

Summary, in English

Resting barley (Hordeum vulgare L.) grains contain acid-proteinase activity. The corresponding enzyme was purified from grain extracts by affinity chromatography on a pepstatin-Sepharose column. The pH optimum of the affinity-purified enzyme was between 3.5 and 3.9 as measured by hemoglobin hydrolysis and the enzymatic activity was completely inhibited by pepstatin a specific inhibitor of aspartic proteinases (EC 3.4.23). Further purification on a Mono S column followed by activity measurements and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the affinity-purified enzyme preparation contained two active heterodimeric aspartic proteinases: a larger 48k Da enzyme, consisting of 32-kDa and 16-kDa subunits and a smaller one of 40 kDa, consisting of 29-kDa and 11-kDa subunits. Separation and partial amino acid sequence analysis of each subunit indicate that the 40-kDa enzyme is formed by proteolytic processing of the 48k Da form. Amino-acid sequence alignment and inhibition studies showed that the barley aspartic proteinase resembles mammalian lysosomal cathepsin D (EC 3.4.23.5).

• Författare: Paula Sarkkinen; Nisse Kalkkinen; Carola Tilgmann; Jari Siuro; Jukka Kervinen; Leena Mikola
• Publiceringsår: 1992-02
• Språk: Engelska
• Sidor: 317-323
• Publikation/Tidskrift/Serie: Planta
• Volym: 186
• Issue: 3
• Länkar: http://dx.doi.org/10.1007/BF00195311
• Dokumenttyp: Artikel i tidskrift
• Förlag: Springer
• Nyckelord: Aspartic proteinase; Cathepsin D; Endopeptidase; Hordeum (proteinase)
• Status: Published
• ISBN/ISSN/Övrigt: ISSN: 0032-0935