Krystyna Stachowiak

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Cathepsin B is a lysosomal cysteine protease exhibiting mainly dipeptidyl carboxypeptidase activity, which decreases dramatically above pH 5.5, when the enzyme starts acting as an endopeptidase. Since the common cathepsin B assays are performed at pH 6 and do not distinguish between these activities, we synthesized a series of peptide substrates(More)
Modifications in angiotensin II and its antagonistic peptides that should have increased in vivo half-lives but not reduced biological activity were studied by determining the effect of alpha-methylation of the tyrosine in position 4. [alpha-Methyltyrosine-4]angiotensin II, synthesized by the solid-phase procedure, showed 92.6 +/- 5.3% pressor activity of(More)
Human cystatin C (HCC) is one of the amyloidogenic proteins to be shown to oligomerize via a three-dimensional domain swapping mechanism. This process precedes the formation of a stable dimer and proceeds particularly easily in the case of the L68Q mutant. According to the proposed mechanism, dimerization of the HCC precedes conformational changes within(More)
Saduria entomon lactate dehydrogenase (LDH-A4*) from thorax muscle was purified about 89 fold to specific activity 510 micromol NADH/min/mg using Cibacron Blue 3GA Agarose and Oxamate-Agarose chromatographies. The enzyme is a tetramer, with molecular weight of 140 kDa for the native enzyme and 36 kDa for the subunit. The isoelectric point was at pH 5.7. The(More)
Human cystatin C (HCC) shows a tendency to dimerize. This process is particularly easy in the case of the L68Q HCC mutant and might lead to formation of amyloid deposits in brain arteries of young adults. Our purpose was to find ligands of monomeric HCC that can prevent its dimerization. Eleven antisense peptide ligands of monomeric HCC were designed and(More)
A rapid and easily interpreted method for peptide mapping is demonstrated with hemoglobin A and three variants. Digests of the globin chains are generated in columns containing immobilized trypsin. The resulting protein fragments are resolved by reverse phase HPLC and then analyzed by thermospray mass spectrometry. The entire process is carried out on-line.(More)
Synthesis and photophysical studies of (O-methyl)-β-tyrosine (β-tyrosine; an analogue of tyrosine, in which the amino group is moved from the α- to the β-carbon, closer to the phenol ring) and its derivatives with a blocked amino and/or carboxyl group were performed to explain the nature of the fluorescence of tyrosine derived analogues. All β-tyrosine(More)
[1-Sarcosine,4-beta-homotyrosine]-(I), [5-beta-homoisoleucine]-(II), and [1-sarcosine,5-beta-homoisoleucine]angiotensin II (III) were synthesized by Merrifield's solid-phase procedure to study the effect of pressor activity and duration of action. The analogues I--III possessed, respectively, 1.98, 2.82, and 29.2% pressor activity of angiotensin II(More)
The arrangement of the disulfide bridges of Cucurbita maxima trypsin inhibitor, CMTI I, has been confirmed by enzymatic and chemical cleavages of the native protein and analysis of the resulting disulfide-bridged fragments using thermospray liquid chromatography/mass spectrometry. Although the disulfide bridges of CMTI I have recently been assigned from the(More)
Papain activity in a buffer containing Me2SO was studied using fluorogenic substrates. It was found that the number of active sites of papain decreases with increasing Me2SO concentration whereas the incubation time, in a buffer containing 3% Me2SO does not affect the number of active sites. However, an increase of papain incubation time in the buffer with(More)