Pyroglutamyl residues, hydrolysis

MH - SO3) consistent with a single sulfate group and a pyroglutamyl residue in the structure. Basic hydrolysis of the... 

Next to trypsin chymotrypsin is the most preferred proteolytic enzyme in sequencing. Its specificity is less absolute than that of trypsin. Primarily the bonds that follow phenylalanine, tyrosine and tryptophan are cleaved, but measurable hydrolysis takes place next to leucine and methionine residues as well. It is advisable, therefore, to determine in preliminary experiments the conditions (enzyme-substrate ratio, time, temperature) best suited for the formation of a few and well separable fragments. Occasionally also less specific enzymes, such as pepsin, papain or thermolysin find application in structure elucidation. For the hydrolysis of specific bonds new microbial proteases can be isolated. There are known prolidases and also enzymes which hydrolyze solely the bond which follows a pyroglutamyl residue and so on. 

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