136553-76-9 BQ 162 BQ-162 Cyclo(D-alpha-glutamyl-L-prolyl-D-valyl-L-leucyl-D-tryptophyl) Cyclo(D-glu-L-pro-D-val-L-leu-D-trp-) Cyclo(glu-pro-val-leu-trp-) Cyclo(glutamyl-prolyl-valyl-leucyl-tryptophyl)