To assess the thrombin specificity of tripeptide chromogenic substrates, we determined the Michaelis--Menten (Km), catalytic (kcat), and specificity (kcat/Km) constants for S-2238 (H-D-Phe-Pip-Arg-p-nitroanilide), Chromozym-TH (Tos-Gly-Pro-Arg-p-nitroanilide), and Spectrozyme-TH (H-D-hexahydrotyrosyl-Ala-Arg-p-nitroanilide) with high-purity thrombin preparations. Human and bovine alpha-thrombin...

OBJECTIVE Neutrophil elastase accounts for the ability of some fresh rheumatoid synovial fluids to degrade cartilage matrix in vitro. The aim of this study was to determine if enzyme activity could result from depletion of synovial fluid inhibitors or protection of the enzyme from inhibition. METHODS The ability of synovial fluids to inhibit porcine pancreatic elastase was investigated togeth...

Seventy-two strains of pediococci isolated from human clinical sources were characterized by conventional physiological tests, chromogenic enzymatic tests, analysis of whole-cell protein profiles (WCPP) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and analysis of chromosomal DNA restriction profiles by pulsed-field gel electrophoresis (PFGE). Conventional tests allowed identifi...

E CLASSIC measurement of a-amylase (a1,4-glucan 4-glucanohydrolase, EC 3.2.1.1) activity in biological fluids is based on enzymatic hydrolysis of a starch substrate. This activity can be assessed either by a saccharogenic procedure (1, ), which measures the increase in reducing sugar (mainly maltose), or by an amyloclastic procedure (1, ), which depends on the decrease or disappearance of the b...

The most common microbiological pathogens of reproductive tract disease in the horse are Streptococcus sp., Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa. The standard approach to the detection of these pathogenic bacteria is to culture the reproductive tracts of the mare or stallion. One or more general purpose media such as horse blood agar (HBA) o...

The synthesis, structure, and anion binding properties of chromogenic octamethylcalix[4]pyrroles (OMCPs) and their N-confused octamethylcalix[4]pyrrole isomers (NC-OMCPs) containing an inverted pyrrole ring connected via alpha'- and beta-positions are described. X-ray diffraction analyses proved the structures of two synthesized isomeric pairs of OMCPs and NC-OMCPs. The addition of anions to so...

This review describes some recent developments in chromogenic and fluorogenic culture media in microbiological diagnostic. The detection of beta-D-glucuronidase (GUD) activity for enumeration of Escherichia coli is well known. E. coli O157:H7 strains are usually GUD-negative and do not ferment sorbitol. These characteristics are used in selective media for these organisms and new chromogenic me...

BACKGROUND To isolate over-secretors, we subjected to saturation mutagenesis, a strain of P.pastoris exporting E. coli alkaline phosphatase (EAP) fused to the secretory domain of the yeast α factor pheromone through cellular PHO1/KEX2 secretory processing signals as the α-sec-EAP reporter protein. Direct chromogenic staining for α-sec-EAP activity is non-specific as its NBT/BCIP substrate cross...

Reactive Oxygen Species (ROS) are compounds derived from oxygen with important implications in biological processes plants, some of them related to reproduction. Among ROS, superoxide is the primary oxidant, since an array other ROS eventually this anion. Therefore, analysis molecular systems able generate molecule and cellular compartmentalization these events paramount importance. We have use...