The present invention provides a modified lactoferrin peptide which is cytotoxic, 7 to 25 amino acids in length, with three or more cationic residues and which has one or more extra bulky and lipophilic amino acids as compared to the native lactoferrin sequence, as well as esters, amides, salts and cyclic derivatives thereof as well as methods of preparing such peptides, pharmaceutical compositions containing such peptides and use of the peptides as medicaments, particularly as antibacterials or anti-tumoural agents.
Chimiak,A., Roczniki Chemii, 1964, vol. 38, p. 883 - 885
作者:Chimiak,A.
DOI:——
日期:——
Acylase I-Catalyzed Deacetylation of <i>N</i>-Acetyl-<scp>l</scp>-cysteine and <i>S</i>-Alkyl-<i>N</i>-acetyl-<scp>l</scp>-cysteines
作者:Vinita Uttamsingh、D. A. Keller、M. W. Anders
DOI:10.1021/tx980018b
日期:1998.7.1
The aminoacylase that catalyzes the hydrolysis of N-acetyl-L-cysteine (NAC) was identified as acylase I after purification by column chromatography and electrophoretic analysis. Rat kidney cytosol was fractionated by ammonium sulfate precipitation, and the proteins were separated by ion-exchange column chromatography, gel-filtration column chromatography, and hydrophobic interaction column chromatography. Acylase activity with NAC and N-acetyl-L-methionine (NAM), a known substrate for acylase I, as substrates coeluted during all chromatographic steps. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the protein was purified to near homogeneity and had a subunit M-r of 43 000, which is identical with the M-r of acylase I from porcine kidney and bovine liver. n-Butylmalonic acid was a slow-binding inhibitor of acylase I and inhibited the deacetylation of NAC with a K-i of 192 +/- 27 mu M These results show that acylase I catalyzes the deacetylation of NAG. The acylase I-catalyzed deacetylation of a range of S-alkyl-N-acetyl-L-cysteines, their carbon and oxygen analogues, and the selenium analogue of NAM was also studied with porcine kidney acylase I. The specific activity of the acylase I-catalyzed deacetylation of these substrates was related to their calculated molar volumes and lag P values. The S-alkyl-N-acetyl-L-cysteines with short (C-0-C-3) and unbranched S-alkyl substituents were good acylase I substrates, whereas the S-alkyl-N-acetyl-L-cysteines with long (>C-3) and branched S-alkyl substituents were poor acylase I substrates. The carbon and oxygen analogues of S-methyl-N-acetyl-L-cysteine and the carbon analogue of S-ethyl-N-acetyl-L-cysteine were poor acylase I substrates, whereas the selenium analogue of NAM was a good acylase I substrate.
Atherton, Eric; Pinori, Masimo; Sheppard, Robert C., Journal of the Chemical Society. Perkin transactions I, 1985, p. 2057 - 2064
作者:Atherton, Eric、Pinori, Masimo、Sheppard, Robert C.