Search results for "peptidase"
showing 10 items of 567 documents
COBALT SUBSTITUTED PROTEINS
1995
Cobalt(II) has been extensively used as a spectroscopic probe in many proteins, mainly replacing zinc, but also substituting iron, manganese and copper ions. The relatively short electronic relaxation times of high spin cobalt(II) makes this ion suitable as a paramagnetic probe for Nuclear Magnetic Resonance spectroscopy. A survey of the NMR studies performed in cobalt substituted proteins is shown. In the zinc enzymes Carboxypeptidase A, Carbonic Anhydrase and Superoxide Dismutase the implications of these studies on their catalytic mechanisms are commented. Finally, a further insight in the research of the blue copper protein Azurin by applying NMR to its cobalt derivative is also reporte…
Azide and chloride binding to carboxypeptidase A in the presence of L-phenylalanine
1990
The interaction of chloride with native and cobalt (Co)-substituted carboxypeptidase-A (CPD) has been investigated by 35Cl nuclear magnetic resonance (NMR) spectroscopy in the presence and absence of L-Phe. The affinity constants of azide and chloride toward the Co(II)CPD·L-Phe complex have been measured by electronic spectroscopy. The correlation times determining T1 and T2 for the 35Cl nuclei are related to movements inside the cavity. In the presence of L-Phe, the anions bind to the metal with a relatively high affinity at pH values below 6. Anion binding to the Co enzyme can be analyzed in terms of the three protonation state model for the enzyme (EH2 α EH α E). In the presence of L-Phe…
Benigne Form der Osteopetrose
2001
Die Osteopetrose ist eine Erkrankung, bei der es zu Resorptionsstorungen des durch enchondrale Ossifikation gebildeten Knochens kommt. Die Ursache der Osteoklasteninsuffizienz ist nicht bekannt. In der Literatur wird ein vollstandiger Syntheseverlust der Zysteinprotease Kathepsin K als Atiologie der Resorptionsstorung diskutiert. Wir konnten in unserem Fallbericht bei der benignen Form der Osteopetrose eine Kathepsin-K-Expression osteoklastarer Zellen nachweisen. Weiterhin fanden wir in den osteoklastaren Zellen den Makrophagenmarker CD68, wobei sich in deren Nachbarschaft keine weiteren Zellen des mononuklearen Phagozytensystems darstellen liesen. Eine Hemmung der osteoklastaren Zellen dur…
Impact of Glucose-Lowering Medications on Cardiovascular and Metabolic Risk in Type 2 Diabetes
2020
Type 2 Diabetes Mellitus (T2DM) is associated with a high risk of atherosclerotic cardiovascular (CV) disease. Among the well-known pathophysiologic factors, crucial roles are played by endothelial dysfunction (caused by oxidative stress and inflammation hyperglycemia-linked), increased activity of nuclear factor kB, altered macrophage polarization, and reduced synthesis of resident endothelial progenitor cells. As consequence, a potentially rapid progression of the atherosclerotic disease with a higher propensity to unstable plaque is arguable, finally leading to significantly increased cardiovascular mortality. Main managements are focused on both prevention and early diagnosis, by target…
Prognostic Impact of let-7e MicroRNA and Its Target Genes in Localized High-Risk Intestinal GIST: A Spanish Group for Research on Sarcoma (GEIS) Study
2020
MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level, and they have been described as being associated with tumor prognosis. Here, miRNA profiling was planned to explore new molecular prognostic biomarkers in localized intestinal high-risk GIST. Paraffin tumor blocks of 14 and 86 patients were used in the discovery and expansion sets, respectively. GeneChip miRNA v3.0 was employed to identify the miRNAs differentially expressed between relapsed and non-relapsed patient samples, which were validated in the expansion set, by qRT-PCR. RT2 Profiler PCR Array was used for the screening of let-7e targets. Expression levels were co…
Cell Surface-Bound Leucine Aminopeptidase: Target of the Immunomodulator Bestatin
1986
The study of low molecular weight enzyme inhibitors of microbial origin was initiated by Umezawa in 1965 (see Umezawa 1972). Since the discovery of an inhibitor of tyrosine hydroxylase, nearly 50 inhibitors of various enzymes have been found by him; their structures were elucidated and most of the compounds were chemically synthesized (Umezawa 1982). Among them one inhibitor of both aminopeptidase B and the ectoenzyme, leucine aminopeptidase was found in 1976 and was termed bestatin (Fig. 1), [(2S,3R)-3-amino-2-hydroxy 4-phenyl-butanoyl]-(S)-leucine (Umezawa et al. 1976).
A practical entry to β-aryl-β-alkyl amino alcohols: application to the synthesis of a potent BACE1 inhibitor
2012
The 1,2-addition of alkyl Grignard reagents to readily available N-tert-butanesulfinyl ketimines, bearing an α-silyloxy substituent, proceeds in high yields and excellent diastereocontrol. The utility of the present method was demonstrated by the synthesis, in enantiomerically pure form, of one recently disclosed β-secretase (BACE1) inhibitor.
Purification and characterization of leucine aminopeptidase from kidney bean cotyledons
1992
A leucine aminopeptidase (EC 3,4,11.1) was purified from cotyledons of resting kidney beans (Phaseolus vulgaris L. cv. Processor) by acidic extraction, ammonium sulfate fractionation and chromatography on DEAE-Sephacel, Sephacryl S-300, Mono Q HPLC and Superose HPLC columns. The yield of the 317-fold purified enzyme was 9%. On gel filtrations on Sephacryl S-300 and Superose HPLC the elution volumes of the enzyme corresponded to an M, of 360 000. The enzyme gave one band on native gel electrophoresis and an electrophoretic titration in an immobilized pH gradient gave a single curve with a pI of 4.8. Two bands were observed in an SDS-gel electrophoresis with Mr values of 58 000 and 60 000 bot…
Inhibitors of endogenous proteinases in the seeds of Scots pine, Pinus sylvestris
1980
Extracts of resting pine seeds inhibited the proteinase activities present in extracts of endosperms of germinating seeds (hydrolysis of haemoglobin at pH 3.7 and hydrolysis of casein at pH 5.4 and 7.0). Heating the extracts of resting seeds at 60°C destroyed their own proteinase activity but their proteinase inhibitor activity decreased by only 25 to 30%. Some properties of the inhibitor(s) were studied using extracts treated at 60°C. The inhibitor activities were non-dialysable. the inhibition increased linearly with increasing inhibitor concentration up to 80% of total proteinase activity, and the maximal inhibition was 80% at pH 3.7. 90% at pH 5.4. and 97% at pH 7.0. The extracts of res…
Comperative studies with Culex pipiens egg rafts. Immunogenetic, electrophoretic and enzymatic analysis of unfertilized, compatible and incompatible …
1973
By applying immunologic, electrophoretic and enzymatic methods, extracts of different raft types of Culex pipiens were analysed. Rafts of the crosses Pa x Pa and Ha x Ha contained four common antigens, while unfertilized rafts of Pa and Ha (no antisera were prepared against them) and rafts of the crosses Og x Og, Og x Pa, and Pa x Og shared three common antigens with the remaining raft extracts. Disk-electrophoresis of raft extracts in acrylamide gel resulted in different electropherograms. Ten protein bands were common to all these raft types. The unfertilized rafts of Pa and Ha yielded three more protein bands, the crosses Pa x Ha and Ha x Pa one more, the crosses Og x Og and Pa x Og thre…