Topic
Esterase
About: Esterase is a research topic. Over the lifetime, 7622 publications have been published within this topic receiving 168270 citations.
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TL;DR: A simple and precise spectrophotometric determination of methanol in the range 2–40 μg is described, which is an improvement on previously described methods and the value of the method in studies of pECTin and pectin esterase metabolism is indicated.
332 citations
TL;DR: A euglobulin fraction of human C'1 has been chromatographically resolved into three distinct activities, designated C' 1q, C’1r, and C's1s, in the order of their elution from DEAE cellulose, shown to participate in various hemolytic reactions requiring C'3, including the cold phase of the Donath-Landsteiner reaction.
Abstract: A euglobulin fraction of human C'1 has been chromatographically resolved into three distinct activities, designated C'1q, C'1r, and C'1s, in the order of their elution from DEAE cellulose. All three of these activities have been shown to participate in various hemolytic reactions requiring C'1, including the cold phase of the Donath-Landsteiner reaction, and to be necessary for generation of C'1 esterase. C'1q was identical with a previously described serum protein implicated in a very early step of complement action and designated the 11S component on the basis of its sedimentation constant. C'1r could not be related to a known complement activity and has been presented as a new component. C'1s, on the basis of chromatographic evidence, was identified with C'1 proesterase. Methods of assay of these components of C'1 have been presented. The significance of C'1q, C'1r, and C'1s in generation of C'1 esterase and the central role of this enzyme in reactions involving C'1, C'4, and C'2 have been discussed.
323 citations
TL;DR: Methylglyoxal modification of critical arginine residues, whether experimental or physiological, is expected to disrupt protein-ligand interactions and inactivate enzyme activity by hydroimidazolone formation.
313 citations
TL;DR: In the course of an investigation of the inhibition of crystalline pancreatic proteolytic enzymes by specific low molecular weight compounds the discovery was made that crystalline trypsin is likewise a powerful catalyst for the hydrolysis of certain amino acid esters.
308 citations
TL;DR: It is demonstrated that clones of murine Tc cells possess considerable trypsin-like esterase activity when assayed by a sensitive colorimetric assay and that the ester enzyme activity resides in a protein of relative molecular mass (Mr) 28,000 (28K).
Abstract: Cytotoxic T (Tc) lymphocytes recognize and lyse target cells and are thought to serve as an important defence against viral infections1 and possibly against neoplasms2. The nature of the receptors responsible for antigen recognition by these cells is becoming clearer, but the molecular mechanisms responsible for their cytolytic activity remain largely unknown. The possibility that proteases are involved in this process has been suggested by the effects of certain inhibitors3,4. Here we demonstrate that clones of murine Tc cells possess considerable trypsin-like esterase activity when assayed by a sensitive colorimetric assay. This activity was blocked completely by two serine esterase inhibitors, diisopropylfluorophosphoridate (DFP) and phenylmethylsulphonyl fluoride (PMSF), but not by Nα-tosyl lysyl chloromethyl ketone (TLCK). The use of 3H-DFP as an affinity-labelling reagent demonstrated that the esterase activity resides in a protein of relative molecular mass (Mr) 28,000 (28K). A wide variety of other lymphocytes, including those from thymus, spleen and lymph node, established lines of B cells and noncytotoxic T cells, and clones of T helper cells, had about 300-fold less esterase activity than the Tc-cell clones and far smaller amounts of the DFP-reactive 28K protein. However, in thymocytes the esterase activity increased 20–50-fold and the 28K protein became more prominent 4 days after these cells had been stimulated in vitro to generate Tc cells.
305 citations