Aspartic proteinase with a high preference for bonds between hydrophobic residues. Cleaves alpha-lactalbumin but not beta-lactoglobulin. Inhibited by the specific aspartic proteinase inhibitors diazoacetyl-noleucine methyl ester and pepstatin. Optimum pH is 5.0. Active from pH 2.0-7.0. Stable at temperatures of up to 60 degrees Celsius. Heterodimer of a light chain and a heavy chain. An intermediate form (35 kDa and 30 kDa subunits) is produced first, and undergoes proteolytic processing to remove the internal plant-specific insert (PSI) and the propeptide. There is some heterogeniety at the cleavage site. Interacts (via RGD or KGE motifs) with PLD1 (via C2 domain). Procardosin-A is associated with the microsomal membranes, the mature form is secreted. Detected only in pistils, not in seeds, roots, midribs, bracts, stamens, pollen, vascular or supporting tissues (PubMed:9362566). Detected in seeds (PubMed:18767217). High amounts are detected in the broad outer region of the upper portion of the stigma, towards the lower portion of the stigma it accumulates at the periphery. Within the stigma, expressed mainly in the epidermic papillae, lower levels are found in the cortical parenchyma. Present mainly in epidermal cells within the stye (at protein level). Expressed in young flower buds, and at lower levels in seeds, pollen and bracteas, but not in roots or leaves. Expressed at the first stages of flower development, and converted into its mature form as the flower matures, accumulating until the later stages of flower senescence. During flower development at the mRNA level, the highest expression is detected in closed capitula and no mRNA was detected at later stages of floral development. At the protein level, highest expression of mature cardosin-A is detected in fully opened capitula. Detected at mRNA level in the embryo fraction of dry seeds. Not detected in developing seeds until 72-84 hours of hydration, where it is detected in the embryo and remains in subsequent developmental stages. At protein level, the precursor form is detected in the hydrated seed until 120 hours, an intermediate form is detected at almost all stages, and the mature protein is detected until 60 hours and reappears before the seedling stage. N-glycosylated. Glycans found at Asn-139 include approximately 6% oligomannose, 82% oligosaccharides of the plant modified type with proximal fucose but without xylose and 6% oligosaccharides of the plant modified type with proximal fucose and xylose. Glycans found at Asn-432 include 14% oligosaccharides of the plant modified type with proximal fucose but without xylose and 86% oligosaccharides of the plant modified type with proximal fucose and xylose. Heavy chain. Light chain. Belongs to the peptidase A1 family.