Antimicrobial peptide | Small intestine | Crypts | Mucus | Luminal content | Retention time HPLC fig 2A | Sequence determined | MALDI-TOF mass (Da) observed (theoretical) | Reference and accession no |
Defensin 1, 2, 3 | + | + | + | – | 51 | LRDLVXYXRT | 4119 (4117), 4249 (4248), 4276 (4275) | 20 |
Defensin 6 | + | + | + | – | 54 | LRDLVXYXRT | 4131 (4131) | 21 |
Defensin 4 | + | + | + | – | 60 | ND | 3758 (3757) | 20 |
CRS4C-3a | + | + | – | – | 58–62 | Sequencing, MALDI-TOF, immunoblot | 4231* (4231) | 5 |
CRS4C-1a | + | + | – | – | 58–62 | Sequencing, MALDI-TOF | 4245* (4245) | 5 |
Thymosin-β | + | + | + | – | 54, 59–60 | AEIEXFDXSK† | 4964, 4981 (4964, 4981‡) 4937, 4952 (4937, 4952§) | 22 |
Ubiquicidin | + | + | + | – | 57 | KVHGSLARXGKVRGQ | 6648 (6654) | 23 |
Ribosomal protein L29 | + | + | + | – | 68 | AKSKNHTTHNQXRKWH, immunoblot | ND (17 456) | NP_033108 |
Phospholipase A2-IIa | + | + | ND | – | 71 | NIAQFGEMIRLKTGKRAEL | 14 002 (14 004) | 3, P31482 |
Ribosomal protein L26 | + | ND | ND | – | 76 | MKFNPKVTSDKSXNR | 17 253 (17 258) | 24, AAH99481 |
Ribosomal protein L38 | + | ND | ND | – | 78 | PRKIEEIKDFLLTARRKDAK | ND (8073) | 25, AAH94644 |
Lysozyme P | + | + | + | – | 86 | KVYNRXELAXILKR, immunoblot | 14 960 (14 956) | 26, AAH61129 |
Ribosomal protein L35 | + | + | + | – | 86 | AKIKAKDLRGKKK | 14 445 (14 421) | 27, NP_079868 |
Extracts of total small intestine, isolated primary crypts, mucus preparation and luminal content were analysed after RP-HPLC separation as shown in fig 2 using MALDI-TOF analysis, N-terminal sequencing or immunoblot.
*Reduced sample. †After cyanogen bromide cleavage. ‡Acetylated and oxidised. §Methylated and oxidised.
CRC, cryptdin-related sequence; MALDI-TOF, matrix-assisted laser desorption-ionisation time-of-flight; ND, not determined; RP-HPLC, reverse phase high-performance liquid chromatography.