The major leucyl aminopeptidase of Trypanosoma cruzi (LAPTc) assembles into a homohexamer and belongs to the M17 family of metallopeptidases

Table 1 Identification of T. cruzi protease by peptide mass fingerprinting

Tryptic peptide masses (Da)		Identified amino acid sequences
Experimental data^a (in-gel digestion)	T. cruzi aminopeptidase (in silico digestion)
2,193.39	2,192.38	³⁶K.THTAGLASTFVVILGTHAQLR.E⁵⁶
2,749.63	2,748.62	³⁶K.THTAGLASTFVVILGTHAQLR↓EDALK.E⁶¹
1,764.03	1,763.02	⁶²K.ELPFYCPAVAEAIQR.V⁷⁶
3,011.58	3,010.57	¹⁸²R.LTVVFTPAPNPSPSELVVVATSTQLCQR.L²⁰⁹
2,437.36	2,436.35	²¹⁰R.LVDAPTNLLNTATFAEVAQSYAK.E²³²
1,742.99	1,741.98	³¹⁰R.DMGGAAAVFCGFLTAVR.L³²⁶
1,977.11	1,976.10	⁴¹²R.HAGIFVNDEEEELSFLK.A⁴²⁸
2,590.34	2,589.34	⁴³²R.VSGETCFPVLYCPEYHVTEFR.S⁴⁵²
1,538.92	1,537.92	⁵⁰⁴K.ATGFGPALLMEYLR.N⁵¹⁷
1,554.90	1,553.89	⁵⁰⁴K.ATGFGPALLM EYLR.N⁵¹⁷

^a Masses are MH⁺ monoisotopic, with accuracy up to 0.2 Da. The enzyme was digested with trypsin, and masses of resulting peptides were determined by MALDI-TOF mass spectrometry and compared to theoretical ones produced by in silico digestion of proteins found in the database (NCBInr). An oxidation of methionine is indicated as M. A missed cleavage is indicated as ↓.

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