Differentiation of intracellular peptidases of starter and adjunct cultures using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Degradation of αs1-CN f1-23 by aminopeptidase N and endopeptidases E, O, O2, and O3 of Lactobacillus helveticus WSU19 under cheese ripening conditions

“…A total of eight spectra (a sum of 256 laser pulses) were collected for each sample. Peptide fragments derived from a s1 -CN f1-23 were determined as described by Soeryapranata et al (2004).…”

“…Studies have been conducted by our group to elucidate the debittering activity of peptidases of Lb. helveticus WSU19 (Fajarrini, 1999;Olson, 1998;Soeryapranata, Powers, Fajarrini et al, 2002;Soeryapranata, Powers, Weller, Hill, & Siems, 2004). Recently, the actions of aminopeptidase N (PepN), endopeptidase E (PepE), endopeptidase O (PepO), endopeptidase O2 (PepO2), and endopeptidase O3 (PepO3) of Lb.…”

The hepatopancreas enzymes of the crustaceans Munida and their potential application in cheese biotechnology

“…Mass spectrometry analysis of the degradation pattern of bitter peptide b-CN f193e209 50 mL of commercial rennet (diluted 1:20 in 20 mM citrate buffer, pH 5.5) were added to 2 mL of 0.5% b-casein in 20 mM citrate buffer, pH 5.5 containing 4% NaCl. After 4 h incubation at 32 C, the reaction was stopped by heating the mixture for 15 min at 75 C and cooled in ice (Soeryapranata, Powers, Weller, Hill, & Siems, 2004). Bitter peptide b-CN f193e209 was isolated by adding ethanol (70% final concentration).…”

Cloning and characterization of debittering peptidases, PepE, PepO, PepO2, PepO3, and PepN, of Lactobacillus helveticus WSU19

“…A total of 8 spectra (a sum of 256 laser pulses) were collected for each sample. The peptide fragments derived from b-CN f193-209 were determined as described by Soeryapranata et al (2004).…”

“…helveticus WSU19 was accompanied by a marked decrease of the 1881-Da peak intensity. Soeryapranata, Powers, Weller, Hill, and Siems (2004) indicated the importance of general aminopeptidase and endopeptidase activities of Lb. helveticus WSU19 in degrading the bitter peptide, b-CN f193-209.…”