Characterization of an Aminopeptidase and a Proline Iminopeptidase from Cabbage Leaves

Abstract

Aminopeptidase, preferring phenylalanine-p-nitroanilide as substrate, and proline iminopeptidase, highly-specific for proline-p-nitroanilide, were isolated from cabbage leaves (Brassica oleraceae var. capitata). As pH optima, 7.2−7.5 for aminopeptidase activity and 8.0−8.5 for proline iminopeptidase were determined. Both peptidases were strongly inhibited by p-chloromercuribenzoic acid, heavy metal ions and urea. The molecular weights were determined by gel filtration to be 56 and 204 kDa, respectively. The iminopeptidase was decomposed during SDS electrophoresis to four subunits of 50 kDa. Minor impurities of myrosinase- associated protein (~70 kDa) were found in both preparations. Preliminary data of their amino acid sequences showed similarities to those of aminopeptidases N (family M1) and proline iminopeptidases (family S33).

Purification and characterization of proline aminopeptidase from chicken intestine

“…Present studies describe purification and characterization of Pro-aminopeptidase (P-AP) from the tissue. The yield of the enzyme was found to be 27.6 mg/kg of the tissue which was found to be higher than similar enzyme reported in cabbage leaves [19]. Extraction of the enzyme from chicken intestinal tissue was carried out using 10 mM phosphate buffer, pH 8.0.…”

“…Finding of a single enzyme exhibiting higher activity towards N-terminal Pro as well as Leu, Ala, Phe residues is very rare. For instance, proline iminopeptidase purified from cabbage leaves is specific for N-terminal Pro residue [19], while phenylalanine specific aminopeptidase from chick pea cotyledon showed higher specific activity towards Phe or Leu [31] and exhibited low activity towards Pro.…”

“…However, much research has been focused on the application of proline specific exopeptidases in the hydrolysate debittering strategies due to the inability of most general aminopeptidases to hydrolyze the imino bond and a unique contribution of Pro-residues in the bitterness of protein hydrolysates [10]. The aminopeptidase has been purified and characterized from plant, animal and bacterial sources [11,12,19].…”

Purification and characterization of aminopeptidase N from chicken intestine with potential application in debittering

“…Aminopeptidases show great promises in removing the bitterness [29][30][31][32]. Currently, there are number of reports of aminopeptidase used efficiently for removal of bitterness of protein hydrolysates [33,34].…”

Enzymatic Hydrolysis of Soy Protein Isolate by Food Grade Proteinases and Aminopeptidases of Plant Origin

“…capitata) and the aminopeptidase from chick-pea cotyledons (Cicer arietinum L.) were purified (12,13,15).…”