Search results for "carboxypeptidase"
showing 9 items of 29 documents
The Complement System: Activation and Control
1985
One of the hallmarks of immunology has been analysis and characterization of the C system in biological fluids. It is composed of 11 proteins of the “classical” pathway:1 C1q, C1r, C1s, C4, C2, C3, C5, C6, C7, C8, and C9. There are three proteins of the “alternative” pathway (IUIS-WHO Nomenclature Committee 1981) B, D, and P. Finally, there are four control proteins: C1 inhibitor (Cl¯ INH) and C4b binding protein (C4b-bp) for the classical pathway, I (C3b inactivator or C3b INA) and H (β1 or C3b INA accelerator) for the alternative pathway, and anaphylatoxin inactivator. Due to the dramatic advances in protein chemistry, these 19 distinct serum proteins have been highly purified and charact…
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…
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…
Activities of some peptidases and proteinases in germinating kidney bean, Phaseolus vulgaris
1986
The activities of aminopeptidase (EC 3.4.11), dipeptidase (EC 3.4.13), carboxypeptidase (EC 3.4.16), naphthylamidase (EC 3.4.11) and proteinases (EC 3.4.21) were assayed in extracts from the cotyledons and the axial tissues of resting and germinating kidney beans (Phaseolus vulgaris L. cv. Processor). The activities of the alkaline peptidases (aminopeptidase hydrolyzing Leu-Tyr at pH 9.2 and dipeptidase acting on Ala-Gly at pH 8.5) and naphthylamidases (hydrolyzing Leu-β-naphthylamide at pH 6.4) were high in the cotyledons of resting seeds, but decreased during germination. This decrease was faster than the loss of the total nitrogen. On the contrary, the activities of carboxypeptidase (hyd…
Acid Carboxypeptidases in Grains and Leaves of Wheat, Triticum aestivum L
1986
Extracts of resting and germinating (3 days at 20 degrees C) wheat (Triticum aestivum L. cv Ruso) grains rapidly hydrolyzed various benzyloxycarbonyldipeptides (Z-dipeptides) at pH 4 to 6. Similar activities were present in extracts of mature flag leaves. Fractionation by chromatography on CM-cellulose and on Sephadex G-200 showed that the activities in germinating grains were due to five acid carboxypeptidases with different and complementary substrate specificities. The wheat enzymes appeared to correspond to the five acid carboxypeptidases present in germinating barley (L Mikola 1983 Biochim Biophys Acta 747: 241-252). The enzymes were designated wheat carboxypeptidases I to V and their …
Localization and Activity of a Carboxypeptidase in Germinating Seeds of Scots Pine, Pinus sylvestris
1976
Extracts prepared from the endosperm of germinating seeds of Scots pine, Pinus sylvestris L., hydrolysed two typical carboxypeptidase substrates, Z-Phe-Ala and Z-Phe-Phe, with pH optima at 4.2 and 5.0. The activities were completely destroyed by diisopropylfluorophosphate. Identical heat inactivation curves and elution patterns in gel chromatography on Sephadex G-200 suggest that the two activities are due to a single enzyme. In resting seeds very low carboxypeptidase activity was present in both the endosperm and the embryo. During germination on agar gel at 20°C in the dark the activities, expressed as enzyme units per seed, increased in the seedling and particularly in the endosperm up t…
The Anaphylatoxic Peptide C3a of Guinea Pig Complement
1978
Abstract Highly purified guinea pig C3a was obtained after specific cleavage of isolated C3 by the alternative pathway enzyme VF-B in a one step procedure. It turned out to be a low molecular weight peptide with basic character (M.W. 9500; isoelectric point above 9.4). C3a represents an antigenetic determinant of its own in the native C3 molecule, different from the B determinant. Guinea pig C3a is resistant to 100°C for 10 minutes. Its smooth muscle contracting activity can be destroyed by trypsin and carboxypeptidase B. These findings indicate that guinea pig C3a is quite similar to human C3a.
Reduced serum protease activity in Complex Regional Pain Syndrome: The impact of angiotensin-converting enzyme and carboxypeptidases.
2021
Complex Regional Pain Syndrome (CRPS) occurs in about 2% of patients after fracture of the limbs. In an earlier clinical study with 102 probands we have shown that the serum protease network in CRPS might be less effective. Based on these results we hypothesized that angiotensin-converting enzyme (ACE) and carboxypeptidase N (CPN) activity contribute to the differences of labeled bradykinin (DBK) degradation by patients' sera. Details of the enzymatic processes remained however unclear. The contributions of ACE and CPN in the serum degradation of DBK were studied using specific inhibitors. CPN1-ELISA was performed in serum. It was confirmed that the majority of DBK was degraded by ACE and C…