Cationic trypsin

K8. Kimland, M., Russick, C., Marks, W. H., and Borgstrom, A., Immunoreactive anionic and cationic trypsin in human serum. Clin. Chem. Acta 184, 31—46 (1989). 

Brodrick JW, Geokas MC, Largman C, Fassett M, Johnson JH. Molecular forms of immunoreactive pancreatic cationic trypsin in pancreatitis patient sera. Am J Physiol 1979 237 E474-80. 

Geokas, M. C., C. Largman, P. R. Dune, J. W. Brodrick, and J. Vollmer. 1981. Immunoreactive forms of cationic trypsin in plasma and ascites of dogs in experimental pancreatitis. 

Proteins from albumin/immunoglobulin-depleted CSF (see Fig. 4) were digested with trypsin and the resultant peptides fractionated by two rounds of chromatography using cation exchange and reversed phase columns. 

Similarly, trypsin has been purihed from ground maize seed flour using STl-agarose, followed by cation exchange chromatography. 

Most work has been carried out on the larger peptide. Controlled hydrolysis with trypsin in the presence of K+ or Na+ gives different results for the loss of ATPase activity. The simple interpretation of these experiments is that the enzyme exists in two different conformations in the presence of these cations. The a-peptide is known to span the membrane, and so can provide a pathway across it for cations. The results of hydrolysis with trypsin have been used to identify the portions of the peptide that span the membrane.46 These portions will not be subject to cleavage, and will therefore be at least 26 residues in length, the minimum length necessary to span the membrane. Five peptides have been identified by this technique, all of which contain a very high frequency of hydrophobic amino acids, and appear to represent the membrane-spanning... 

K, Tanizawa, Y Kasaba, and Y. Kanaoka- Inverse substrates" for trypsin. Efficient hydrolysis of certain esters with a cationic center in the leaving group J. Am. Chem. 

For the first time, inverse substrates provide a general method for the specific introduction of an acyl group into the trypsin active site without recourse to cation-containing acyl compounds. The preparation of various new acyl enzymes is expected to lead to the discovery of novel features of the enzymatic reaction mechanism. In addition, any desired reporter groups might be specifically introduced into the trypsin... 

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