Diversity of amyloid beta peptide actions.

Fibril formation by amyloidogenic proteins and peptides is considered the cause of a number of incurable diseases. One of the most known amyloid diseases is Alzheimer's disease (AD). Traditionally, amyloidogenic beta peptides Aβ40 and Aβ42 (Aβs) are considered as main causes of AD and the foremost targets in AD fight.

Citrullination of adenosine deaminase impairs its binding to dipeptidyl peptidase IV.

The presence of citrullinated adenosine deaminase (ADA) was reported in the synovial fluids of rheumatoid arthritis individuals. This work reports the effects of ADA citrullination on the formation/stabilization of ADA complex with dipeptidyl peptidase IV (DPPIV). The electrophoretic mobility of in vivo citrullinated ADA was diminished compared to the native one.

Adenosine deaminase - A target for new piperazine derivatives.

The level of adenosine deaminase (ADA) activity increases in pathological effusions. Therefore, the concentration of its substrate, anti-inflammatory adenosine, decreases, thereby aggravating inflammation. Hence, the quest for ADA inhibiting compounds is an actual problem in medicine and pharmacology.

Concerted action of dipeptidyl peptidase IV and glutaminyl cyclase results in formation of pyroglutamate-modified amyloid peptides in vitro.

Compelling evidence suggests a crucial role of amyloid beta peptides (Aβ(1-40/42)) in the etiology of Alzheimer's disease (AD). The N-terminal truncation of Aβ(1-40/42) and their modification, e.g.

Interaction of dipeptydil peptidase IV with amyloid peptides.

Unlabelled: The aggregates of amyloid beta peptides (Aβs) are regarded as one of the main pathological hallmarks of Alzheimer's disease (AD). An imbalance between the rates of synthesis and clearance of Aβs is considered to be a possible cause for the onset of AD. Dipeptidyl peptidases II and IV (DPPII and DPPIV) are serine proteases removing N-terminal dipeptides from polypeptides and proteins with proline or alanine on the penultimate position.

Proline-rich cytokine from neurosecretory granules: a new natural substrate for dipeptidyl peptidase IV.

A proline-rich cytokine from neurosecretory granules of bovine neurohypophysis, 15 amino acids containing PRP-1 (Ala-Gly-Ala-Pro-Glu-Pro-Ala-Glu-Pro-Ala-Gln-Pro-Gly-Val-Tyr), had been demonstrated as a unique regulator of activity of neurons, strong antibacterial agent, and mediator of the hypothalamus-neurohypophysis-bone marrow-thymus axis, which participates in hematopoietic stem cells differentiation. In the present work it was shown that this neuropeptide represents a new natural substrate for Dipeptidyl Peptidase IV (DPPIV). The time-dependent increase of primary amines quantity in the assay mixture of PRP-1 and DPPIV has been observed allowing to conclude, that DPPIV catalyses the enzymatic reaction of PRP-1 cleavage.

Complex of dipeptidyl peptidase II with adenosine deaminase.

Dipeptidyl peptidase II (DPPII) from bovine kidney cortex and lung was purified to the electrophoretically homogeneous state. The molecular and catalytic characteristics of the enzyme were determined. It was revealed that DPPII preparations possess adenosine deaminase (ADA) activity at all purification steps.

Influence of dipeptidyl peptidase IV on enzymatic properties of adenosine deaminase.

The importance of ADA (adenosine deaminase) in the immune system and the role of its interaction with an ADA-binding cell membrane protein dipeptidyl peptidase IV (DPPIV), identical to the activated immune cell antigen, CD26, has attracted the interest of researchers for many years. To investigate the specific properties in the structure-function relationship of the ADA/DPPIV-CD26 complex, its soluble form, identical to large ADA (LADA), was isolated from human blood serum, human pleural fluid and bovine kidney cortex. The kinetic constants (Km and Vmax) of LADA and of small ADA (SADA), purified from bovine lung and spleen, were compared using adenosine (Ado) and 2'-deoxyadenosine (2'-dAdo) as substrates.

ADA2 isoform of adenosine deaminase from pleural fluid.

Adenosine deaminase isoenzyme 2 (ADA2) was isolated from human pleural fluid for the first time. Molecular and kinetic properties were characterized. It was shown that the inhibitors of adenosine deaminase isoenzyme 1 (ADA1), adenosine, and erithro-9-(2-hydroxy-3-nonyl)adenine (EHNA) derivatives are poor inhibitors of ADA2.

Computational, spectroscopic, and resonant mirror biosensor analysis of the interaction of adrenodoxin with native and tryptophan-modified NADPH-adrenodoxin reductase.

In steroid hydroxylation system in adrenal cortex mitochondria, NADPH-adrenodoxin reductase (AR) and adrenodoxin (Adx) form a short electron-transport chain that transfers electrons from NADPH to cytochromes P-450 through FAD in AR and [2Fe-2S] cluster in Adx. The formation of [AR/Adx] complex is essential for the electron transfer mechanism in which previous studies suggested that AR tryptophan (Trp) residue(s) might be implicated. In this study, we modified AR Trps by N-bromosuccinimide (NBS) and studied AR binding to Adx by a resonant mirror biosensor.

QSAR analysis for ADA upon interaction with a series of adenine derivatives as inhibitors.

The kinetic parameters of adenosine deaminase such as Km and Ki were determined in the absence and presence of adenine derivatives (R1-R24) in sodium phosphate buffer (50 mM; pH 7.5) solution at 27 degrees C. These kinetic parameters were used for QSAR analysis.

Activity of adenosine deaminase and its isoforms in pleural fluid in tuberculous pleuritis.

Background: The problem of tuberculosis is increasing in a number of countries. Adenosine deaminase activity is considered in many clinics to be a valuable biochemical test of this pathology. Considerable research has been devoted to the activity of enzyme isoforms as significant tests for diagnosing tuberculosis.

Interaction of adenosine deaminase with inhibitors. Chemical modification by diethyl pyrocarbonate.

The interaction of adenosine deaminase (adenosine aminohydrolase, ADA) from bovine spleen with inhibitors--erythro-9-(2-hydroxy-3-nonyl)adenine, erythro-9-(2-hydroxy-3-nonyl)-3-deazaadenine, and 1-deazaadenosine--was investigated. Using selective chemical modification by diethyl pyrocarbonate (DEP), the possible involvement of His residues in this interaction was studied. The graphical method of Tsou indicates that of six His residues modified in the presence of DEP, only one is essential for ADA activity.

Tryptophan environment in adenosine deaminase. I. Enzyme modification with N-bromosuccinimide in the presence of adenosine and EHNA analogues.

Adenosine deaminase from bovine cerebral hemisphere (white and gray matter) and spleen was treated with N-bromosuccinimide, a reagent known to oxidize selectively tryptophan residues in proteins. Spectrally observable tryptophan modification was accompanied by enzyme inactivation. Tsow graphics revealed that two Trps are essential for the activity of enzyme from both tissues.

Activity of enzymes of adenyline compounds metabolism during crush and decompression of muscle tissue. Part II. Adenosine deaminase activity at experimental crush syndrome.

Introduction: Publications on investigation of crush syndrome pathogenesis, particularly of enzymatic systems upon traumatic toxicosis are rather limited. Such investigations are necessary for opportune diagnosis and definition of a treatment tactic. To replenish this deficiency, the adenosine deaminase level was studied in 12 rat tissues at experimental crush syndrome in vivo.

Activity of enzymes of adenyline compounds metabolism during crush and decompression of muscle tissue. Part I. Adenylate deaminase activity at experimental crush syndrome.

Introduction: The number of works on investigation of crush syndrome (CS) pathogenesis, of organs and enzymatic systems at traumatic toxicosis is rather limited. While the clinical current of trauma and the lethality prognosis depend on a degree of violations in them. Such investigations are necessary for opportune diagnosis and definition of a treatment tactic.

The effect of detergents on bovine adrenal ferredoxin.

The incubation of adrenal ferredoxin with various detergents in the presence of oxygen or ferricyanide leads to bleaching of the protein. The bleached preparation has the properties of apoferredoxin and it can be reconstituted with high yield by conventional methods.