Table 2.

Initial peptide degradation rates at 50°C. Results for no Cu²⁺ and + Cu²⁺

Initial degradation ratea (% intact peptide loss/ hour)
pHb	Linear, No Cu2+	Linear + 0.15mM Cu2+	Cyclic + 0.15mM Cu2+
5	0.053	0.15	0.081
6	0.043	2.3	–
7	0.060	2.8	1.9

^aLinear regression plot based on intensity of the intact parent peptide peak obtained using RP-HPLC

^bIncubated in sodium acetate (pH 5); MES (pH 6), or HEPES (pH 7) buffer