Purification procedure for the isolation of a P-I metalloprotease and an acidic phospholipase A2 from Bothrops atrox snake venom

Background Snake venoms are complex mixtures of inorganic and organic components, mainly proteins and peptides. Standardization of methods for isolating bioactive molecules from snake venoms is extremely difficult due to the complex and highly variable composition of venoms, which can be influenced by factors such as age and geographic location of the specimen. Therefore, this study aimed to standardize a simple purification methodology for obtaining a P-I class metalloprotease (MP) and an acidic phospholipase A2 (PLA 2 ) from Bothrops atroxvenom, and biochemically characterize these molecules to enable future functional studies.Methods To obtain the toxins of interest, a method has been standardized using consecutive isolation steps. The purity level of the molecules was confirmed by RP-HPLC and SDS-PAGE. The enzymes were characterized by determining their molecular masses, isoelectric points, specific functional activity and partial amino acid sequencing.Results The metalloprotease presented molecular mass of 22.9 kDa and pI 7.4, with hemorrhagic and fibrin(ogen)olytic activities, and its partial amino acid sequence revealed high similarity with other P-I class metalloproteases. These results suggest that the isolated metalloprotease is Batroxase, a P-I metalloprotease previously described by our research group. The phospholipase A 2 showed molecular mass of 13.7 kDa and pI 6.5, with high phospholipase activity and similarity to other acidic PLA2 s from snake venoms. These data suggest that the acidic PLA2 is a novel enzyme from B. atrox venom, being denominated BatroxPLA 2 .Conclusions The present study successfully standardized a simple methodology to isolate the metalloprotease Batroxase and the acidic PLA 2 BatroxPLA2 from the venom of B. atrox, consisting mainly of classical chromatographic processes. These two enzymes will be used in future studies to evaluate their effects on the complement system and the inflammatory process, in addition to the thrombolytic potential of the metalloprotease.

Isolation of the first IMP-4 metallo beta lactamase producing Klebsiella pneumoniae in Tianjin, China

This study shows for the first time the mechanism of carbapenem resistance of a Klebsiella pneumoniae clinical isolate TJ8 recovered from Tianjin medical university general hospital ,China. The modified Hodge test and EDTA synergy test were performed for the screening of carbapenemases and metallo-β-lactamases (MBLs), respectively. Polymerase chain reactions and DNA sequencing confirmed that the strain carried IMP-4 metallo-β-lactamase (MBL) , SHV-11 and TEM-1 β-lactamase. ClassⅠintegron was positive and gave a 3.0-kb PCR amplicon .IMP-4 was located in ClassⅠintegron 5'CS. The gene determinants were organized in the order of blaIMP-4-orfII-orfIII.In all, the results show that IMP-4 MBL production caused the TJ8 resistance to carbapenems.

Action of neuwiedase, a metalloproteinase isolated from bothrops neuwiedi venom, on skeletal muscle: an ultrastructural and immunocytochemistry study

The damaging effects of neuwiedase, a non-hemorrhagic snake venom metalloproteinase from P-I class, on gastrocnemius muscle are studied herein. Following neuwiedase injection, ultrastructural alterations were detected early showing disarrangement of skeletal muscle fibers (characterized by discontinuity of Z lines), mitochondrial swelling, and disruption of plasma membrane and basal lamina. Degradation of skeletal muscle and the appearance of an amorphous substance, primarily composed of cellular debris, were noted after 24 hours. The presence of neuwiedase at the injection site (detected by immunocytochemistry) revealed highly specific labeling of myofibril components of damaged myocytes. In addition, proteolysis of muscle proteins assayed through myofibrils extracted from gastrocnemius muscle indicated that neuwiedase provoked degradation of myofibrils, especially myosin. These results suggest that skeletal muscle damage, induced by neuwiedase, is probably due to its proteolytic action on myofibrils, which are responsible for the maintenance of the cellular architecture.

Modulation of staphylokinase-dependent plasminogen activation by mono- and divalent ions

The effect of several ions (Cl-, Na+, K+, Ca2+) on the rate of plasminogen (Pg) activation by recombinant staphylokinase (rSTA) is reported. Both monovalent and divalent ions affect the rate at which Pg is activated by rSTA, in a concentration-dependent manner (range 0-100 mM). In almost all cases, a decrease of the initial velocity of activation was observed. Cl- showed the most striking inhibitory effect at low concentrations (64 percent at 10 mM). However, in the presence of a fibrin surface, this inhibition was attenuated to 38 percent. Surprisingly, 10 mM Ca2+ enhanced the Pg activation rate 21 percent when a polymerized fibrin matrix was present. These data support the idea that ions can modulate the rate of Pg activation through a mechanism that may be associated with changes in the molecular conformation of the zymogen. This effect is strongly dependent on the presence of a fibrin clot

A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide

A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 µM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. With Mr 85 kDa, the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 µM) and for atrial natriuretic peptide (Km = 5 µM) suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones

Transición de la forma enzimática latente a activa como un modelo de regulación de la degradación de matriz extracelular en el corioamnios durante el trabajo de parto humano / Transition from the laten to active enzymatic form asa regulation model for the degradation of choriomniotic extracelular matrix during human labor

Las metaloprotesas de matriz extracelular (MMP) son las mediadoras fisiológicas de la degradación de la colágena y su participación en la fisiopatogenia de la ruptura prematura de membranas ha sido sugerida por nuestro grupo. Con objeto de definir si algunas MMP se activan de manera coordinada con el trabajo de parto en las membranas fetales, analizamos la actividad enzimática y proteína inmunorreactiva presente en extractos de membranas obtenidas durante cesáreas, sin trabajo de parto, aunque su actividad/cantidad fue apenas detectable. En cambio los extractos de membranas fetales obtenidas durante el trabajo de parto activo, mostraron gran actividad/cantidad de ésta MMP. Con ayuda de un anticuerpo monoclonal, fue posible demostrar que la forma activa de la MMP-9 se podía encontrar sólo en las muestras con trabajo de parto. La MMP-9 y su ARN mensajero correspondiente fueron localizados por inmunohistoquímica e hibridación in situ en el epitelio amniótico, en algunos fibroblastos de la capa compacta y en células con características de trofoblasto en el corion. Se concluye que: 1. La actividad y la cantidad de la MMP-9 se incrementa de manera selectiva asociada al trabajo de parto y 2. que esta enzima es expresada por diferentes poblaciones celulares de la membrana fetal