. 2005 Jun;71(6):3025–3032. doi: 10.1128/AEM.71.6.3025-3032.2005

TABLE 5.

Specific activities of CFEs of L. lactis LM0230 expressing L. helveticus CNRZ32 endopeptidases towards β-CN (f193-209) and α_S1-CN (f1-9) in a single-peptide reaction, in the defined peptide mix, and in Cheddar cheese serum

Peptide and peptidase^b	Mean (SD) spact in^a:
Peptide and peptidase^b	Single-peptide reaction	Defined peptide mix	Cheddar cheese serum
β-CN (f193-209)
Control	16 (2.0)^†,*	9.0 (2.0)^†,†	27 (3.0)^‡,*
PepE	ND	ND	ND
PepO2	64 (1.5)*^,†	42 (10)^,	120 (32)^,
PepO3	81 (7.0)^,	40 (6.0)^,	61 (23)^†,*
α_S1-CN (f1-9)^c
Control	4.0 (4.0)^‡,*	4.0 (0.2)^§,*	23 (3.0)^‡,†
PepE	190 (14)^,	120 (7)*^,†	31 (17)^‡,‡
PepO2	240 (10)^,	84 (20)^†,‡	150 (40)*^,†
PepO3	41 (19)^†,*	38 (9.0)^‡,*	63 (25)^†,*

Specific activity is measured in nmoles of substrate hydrolyzed per h per mg of protein. Values were corrected by subtracting the mean values obtained in the control treatments from CFE of L. lactis LM0230(pTRKH2). Means with different symbols are statistically different at an α value of ≤0.05. Lightface symbols compare values within a column, and boldface symbols compare values within a row. Assays were performed under cheese-ripening conditions (pH 5.0 to 5.2, 4% NaCl, 10°C). ND, not detected.

CFEs were prepared from L. lactis LM0230(pTRKH2) (control), L. lactis LM0230(pSUW666) (PepE), L. lactis LM0230(pSUW665) (PepO2), or L. lactis LM0230(pSUW664) (PepO3).

In the case of α_S1-CN (f1-9) hydrolysis, average specific activities are reported.