Action of cathepsin D on fructose-1,6-bisphosphate aldolase.
Cathepsin D inactivated aldolase at pH values between 4.2 and 5.2; the chloride, sulphate or iodide, but not citrate or acetate, salts of sodium or potassium accelerated the rate of inactivation. Cathepsin D cleaved numerous peptide bonds in the C-terminus of aldolase, but the major site of cleavage in this region was Leu354-Phe355. The most prominent peptide products of hydrolysis were Phe-Ile-Ser-Asn-His-Ala-Tyr and Phe-Ile-Ser-Asn-His. Up to 20 amino acids were removed from the C-terminus of aldolase, but no further degradation of native aldolase was observed. By contrast, extensive degradation of the 40 000-Mr subunit was observed after aldolase was denatured. The cathepsin D-inactivated aldolase cross-reacted with antibodies prepared against native aldolase and had the same thermodynamic stability as native aldolase, demonstrated by differential scanning calorimetry and fluorescence quenching of tryptophan residues. Furthermore, the cathepsin-modified and native forms of aldolase were both resistant to extensive proteolysis by other purified cellular proteinases and lysosomal extracts at pH values of 4.8-8.0.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002402:Cathepsin D; D002403:Cathepsins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis; D011487:Protein Conformation; D011817:Rabbits; D014508:Urea
D000596:Amino Acids; D046911:Macromolecular Substances; D010455:Peptides; D014508:Urea; D002403:Cathepsins; D002402:Cathepsin D; D005634:Fructose-Bisphosphate Aldolase