锝标记肽对半胱氨酸激发的稳定性比较
Comparison of the stability of technetium-labeled peptides to challenge with cysteine.
作者信息
Stalteri M A, Bansal S, Hider R, Mather S J
机构信息
Imperial Cancer Research Fund, Department of Nuclear Medicine, St. Bartholomew's Hospital, West Smithfield, London EC1A 7BE, U.K.
出版信息
Bioconjug Chem. 1999 Jan-Feb;10(1):130-6. doi: 10.1021/bc9800466.
We have labeled a series of short peptides with technetium-99m either by direct labeling at pH 11 or by exchange from [99mTc]technetium glucoheptonate. Typical labeling yields obtained were as follows: N-acetyl-Gly-Cys(S-Acm)-Gly-Cys(S-Acm)-Gly-NH2 (Acm = acetamidomethyl) 99%, S-benzoyl-mercaptoacetyltriglycine (S-Benzoyl-MAG3) 95%, mercaptoacetyldiglycine-NH2 (MAG2-NH2) 94%, MAG3 92%, N-acetyl-Aib-Aib-Cys-NH2 (Aib = aminoisobutyric acid) 91%, Gly-Gly-Gly-Gly 90%, N-acetyl-Gly-Gly-Cys-Gly 87%, cyclo-1, 4-(Gly-Gly-Gly-Gln) 40%, S-methyl-MAG2-NH2 0%. In the absence of cysteine, all of the labeled peptides were quite stable in solution, with at least 80-90% of the labeled peptide remaining at 24 h. The order of stability of the labeled peptides to challenge with cysteine was found to be MAG3 > S-benzoyl-MAG3 > N-acetyl-Gly-Cys(S-Acm)-Gly-Cys(S-Acm)-Gly-NH2 >N-acetyl-Aib-Aib-Cys-NH2 > MAG2-NH2 > N-acetyl-Gly-Gly-Cys-Gly > cyclo-1,4-(Gly-Gly-Gly-Gln) > Gly-Gly-Gly-Gly. The peptides without a sulfur donor were least stable to challenge with cysteine.
我们通过在pH 11下直接标记或从[99mTc]葡庚糖酸锝进行交换，用99m锝标记了一系列短肽。获得的典型标记产率如下：N-乙酰基-甘氨酸-半胱氨酸（S-乙酰氨基甲基）-甘氨酸-半胱氨酸（S-乙酰氨基甲基）-甘氨酸-NH2（Acm = 乙酰氨基甲基）99%，S-苯甲酰基-巯基乙酰三甘氨酸（S-苯甲酰基-MAG3）95%，巯基乙酰二甘氨酸-NH2（MAG2-NH2）94%，MAG3 92%，N-乙酰基-氨基异丁酸-氨基异丁酸-半胱氨酸-NH2（Aib = 氨基异丁酸）91%，甘氨酸-甘氨酸-甘氨酸-甘氨酸90%，N-乙酰基-甘氨酸-甘氨酸-半胱氨酸-甘氨酸87%，环-1,4-（甘氨酸-甘氨酸-甘氨酸-谷氨酰胺）40%，S-甲基-MAG2-NH2 0%。在没有半胱氨酸的情况下，所有标记的肽在溶液中相当稳定，24小时时至少有80 - 90%的标记肽残留。发现标记肽对半胱氨酸攻击的稳定性顺序为MAG3 > S-苯甲酰基-MAG3 > N-乙酰基-甘氨酸-半胱氨酸（S-乙酰氨基甲基）-甘氨酸-半胱氨酸（S-乙酰氨基甲基）-甘氨酸-NH2 > N-乙酰基-氨基异丁酸-氨基异丁酸-半胱氨酸-NH2 > MAG2-NH2 > N-乙酰基-甘氨酸-甘氨酸-半胱氨酸-甘氨酸 > 环-1,4-（甘氨酸-甘氨酸-甘氨酸-谷氨酰胺） > 甘氨酸-甘氨酸-甘氨酸-甘氨酸。没有硫供体的肽对半胱氨酸攻击最不稳定。
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