Reaction SMILES: [CH3:1][CH2:2][C@@H:3]([C@H:5]([NH:197][C:198]([CH2:200][NH2:201])=[O:199])[C:6]([NH:8][CH2:9][C:10]([NH:12][C@H:13]([C:15]([NH:17][C@H:18]([C:22]([NH:24][C@H:25]([C:30]([NH:32][C@H:33]([C:39]([NH:41][C@H:42]([C:46]([NH:48][C@H:49]([C:54]([NH:56][C@H:57]([C:61]([NH:63][C@H:64]([C:68]([NH:70][CH2:71][C:72]([NH:74][C@H:75]([C:80]([N:82]1[C@H:86]([C:87]([NH:89][C@H:90]([C:92]([NH:94][C@H:95]([C:100]([NH:102][C@H:103]([C:108]([NH:110][C@H:111]([C:114]([NH:116][C@H:117]([C:128]([NH:130][C@H:131]([C:136]([NH:138][C@H:139]([C:145]([NH:147][C@H:148]([C:156]([NH:158][C@H:159]([C:165]([NH:167][C@H:168]([C:176]([NH:178][C@H:179]([C:185]([NH:187][C@H:188]([C:194]([NH2:196])=[O:195])[CH2:189][CH2:190][C:191]([NH2:193])=[O:192])=[O:186])[CH2:180][CH2:181][C:182]([NH2:184])=[O:183])=[O:177])[CH2:169][CH2:170][CH2:171][NH:172][C:173]([NH2:175])=[NH:174])=[O:166])[CH2:160][CH2:161][CH2:162][CH2:163][NH2:164])=[O:157])[CH2:149][CH2:150][CH2:151][NH:152][C:153]([NH2:155])=[NH:154])=[O:146])[CH2:140][CH2:141][CH2:142][CH2:143][NH2:144])=[O:137])[C@H:132]([CH2:134][CH3:135])[CH3:133])=[O:129])[CH2:118][C:119]2[C:123]3[CH:124]=[CH:125][CH:126]=[CH:127][C:122]=3[NH:121][CH:120]=2)=[O:115])[CH2:112][OH:113])=[O:109])[C@H:104]([CH2:106][CH3:107])[CH3:105])=[O:101])[CH2:96][CH:97]([CH3:99])[CH3:98])=[O:93])[CH3:91])=[O:88])[CH2:85][CH2:84][CH2:83]1)=[O:81])[CH2:76][CH:77]([CH3:79])[CH3:78])=[O:73])=[O:69])[C@H:65]([OH:67])[CH3:66])=[O:62])[C@H:58]([OH:60])[CH3:59])=[O:55])[CH2:50][CH:51]([CH3:53])[CH3:52])=[O:47])[CH:43]([CH3:45])[CH3:44])=[O:40])[CH2:34][CH2:35][CH2:36][CH2:37][NH2:38])=[O:31])[CH2:26][CH:27]([CH3:29])[CH3:28])=[O:23])[CH:19]([CH3:21])[CH3:20])=[O:16])[CH3:14])=[O:11])=[O:7])[CH3:4].O[N:203]1[C:224](=[O:225])[NH:223][C@H:222]2[C@@H:204]1[CH2:205][S:206][C@H:207]2[CH2:208][CH2:209][CH2:210][CH:211](N1C(=O)CCC1=O)[C:212](=[O:214])[OH:213]>P([O-])([O-])([O-])=O.[Na+].[Na+].[Na+]>[CH3:1][CH2:2][C@@H:3]([C@H:5]([NH:197][C:198]([CH2:200][NH2:201])=[O:199])[C:6]([NH:8][CH2:9][C:10]([NH:12][C@H:13]([C:15]([NH:17][C@H:18]([C:22]([NH:24][C@H:25]([C:30]([NH:32][C@H:33]([C:39]([NH:41][C@H:42]([C:46]([NH:48][C@H:49]([C:54]([NH:56][C@H:57]([C:61]([NH:63][C@H:64]([C:68]([NH:70][CH2:71][C:72]([NH:74][C@H:75]([C:80]([N:82]1[C@H:86]([C:87]([NH:89][C@H:90]([C:92]([NH:94][C@H:95]([C:100]([NH:102][C@H:103]([C:108]([NH:110][C@H:111]([C:114]([NH:116][C@H:117]([C:128]([NH:130][C@H:131]([C:136]([NH:138][C@H:139]([C:145]([NH:147][C@H:148]([C:156]([NH:158][C@H:159]([C:165]([NH:167][C@H:168]([C:176]([NH:178][C@H:179]([C:185]([NH:187][C@H:188]([C:194]([NH2:196])=[O:195])[CH2:189][CH2:190][C:191]([NH2:193])=[O:192])=[O:186])[CH2:180][CH2:181][C:182]([NH2:184])=[O:183])=[O:177])[CH2:169][CH2:170][CH2:171][NH:172][C:173]([NH2:175])=[NH:174])=[O:166])[CH2:160][CH2:161][CH2:162][CH2:163][NH2:164])=[O:157])[CH2:149][CH2:150][CH2:151][NH:152][C:153]([NH2:155])=[NH:154])=[O:146])[CH2:140][CH2:141][CH2:142][CH2:143][NH2:144])=[O:137])[C@H:132]([CH2:134][CH3:135])[CH3:133])=[O:129])[CH2:118][C:119]2[C:123]3[CH:124]=[CH:125][CH:126]=[CH:127][C:122]=3[NH:121][CH:120]=2)=[O:115])[CH2:112][OH:113])=[O:109])[C@H:104]([CH2:106][CH3:107])[CH3:105])=[O:101])[CH2:96][CH:97]([CH3:98])[CH3:99])=[O:93])[CH3:91])=[O:88])[CH2:85][CH2:84][CH2:83]1)=[O:81])[CH2:76][CH:77]([CH3:78])[CH3:79])=[O:73])=[O:69])[C@H:65]([OH:67])[CH3:66])=[O:62])[C@H:58]([OH:60])[CH3:59])=[O:55])[CH2:50][CH:51]([CH3:53])[CH3:52])=[O:47])[CH:43]([CH3:45])[CH3:44])=[O:40])[CH2:34][CH2:35][CH2:36][CH2:37][NH2:38])=[O:31])[CH2:26][CH:27]([CH3:29])[CH3:28])=[O:23])[CH:19]([CH3:21])[CH3:20])=[O:16])[CH3:14])=[O:11])=[O:7])[CH3:4].[OH:214][C:212]([CH2:211][CH2:210][CH2:209][CH2:208][C@H:207]1[C@@H:222]2[C@@H:204]([NH:203][C:224]([NH:223]2)=[O:225])[CH2:205][S:206]1)=[O:213]
Reactant: O=C(O)C(CCC[C@@H]1SC[C@H]2[C@@H]1NC(=O)N2O)N1C(=O)CCC1=O
Agent: CC[C@H](C)[C@H](NC(=O)CN)C(=O)NCC(=O)N[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@H](C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N1CCC[C@H]1C(=O)N[C@@H](C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@@H](CO)C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N[C@H](C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](CCC(N)=O)C(N)=O)[C@@H](C)CC)[C@@H](C)CC)[C@@H](C)O)[C@@H](C)O)C(C)C)C(C)C
Agent: O=P([O-])([O-])[O-]
Agent: [Na+]
Product: O=C(O)CCCC[C@@H]1SC[C@@H]2NC(=O)N[C@@H]21
Reaction time: 2 h

Procedure:
Melittin (1.7 mg) was dissolved in 2 ml of 0.15M sodium phosphate, pH 7.8. To this solution was added 5 mg of N-hydroxysuccinimidobiotin, available commercially from a number of suppliers, and the biotinylation reaction was allowed to proceed at 25° C. for 2 hours. During this time, a large precipitate formed. The precipitate was collected by contrifugation and then dissolved in 1.5 ml of 0.1M sodium acetate buffer, pH 5.6. This sample was then chromatographed on a Sephadex G-25 column (1.5×40 cm) equilibrated in 0.1M sodium acetate, pH 5.6. The melittin-biotin conjugate was identified in the column eluate by monitoring the absorbance at 280 nm. The peak fractions were pooled and stored at 4° C.