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. Author manuscript; available in PMC: 2009 Jun 25.
Published in final edited form as: Tetrahedron Lett. 2007 Jul 16;48(29):5107–5110. doi: 10.1016/j.tetlet.2007.05.082

Table 1.

Characterization of peptides.

no. peptides ring size % purity tRc min MSd (M + H)+
HPLCa CZEb calcd. obsd.
7 cyclo(2-7)[DPhe1-Cys2-Phe3-DTrp4-Lys5-Thr6-Cys7-Thr8-NH2] (Octreotide-amide) 20 99 99 17.4 1032.436 1032.404
8 DPhe1-Ncy(tBu2-Phe3-DTrp4-Lys5-Thr6-Ncy(tBu)7-Thr8-NH2 - 98 99 35.8 1118.546 1118.502
9 cyclo(2-7)[DPhe1-Ncy2-Phe3-DTrp4-Lys5-Thr6-Ncy7-Thr8-NH2] 18 99 99 14.9 1004.405 1004.341
a

Percentage purity determined by HPLC using buffer A: TEAP, pH 2.30, buffer B: 60% CH3CN/40% A under gradient conditions (20% to 50% B over 30 min), at flow rate of 0.2 mL/min on a Vydac C18 column (0.21 cm × 15 cm, 5 μm particle size, 300 Å pore size). Detection at 214 nm.

b

Percentage purity determined by capillary zone electrophoresis (CZE) using a Beckman P/ACE System 2050 controlled by an IBM Personal system/2 model 50Z; field strength of 15 kV at 30 °C. Buffer, 100 mM sodium phosphate (85:15, H2O:CH3CN), pH 2.50, on a Agilent μSil bare fused-silica capillary (75 μm i.d. × 40 cm length). Detection at 214 nm.

c

Retention times under HPLC conditions described above.

d

Mass spectra (MALDI-MS) were measured on an ABI-Voyager DE-STR instrument using saturated solution of α-cyano-4-hydroxycinnamic acid in 0.3% trifluoroacetic acid and 50% acetonitrile as matrix. The calculated [M + H] of the monoisotope was compared with the observed [M + H]+ monoisotopic mass.