Extracellular Esterase Research Articles

Transport of extracellular esterase into membrane vesicles of Candida lipolytica [proceedings

Transport of extracellular esterase into membrane vesicles of Candida lipolytica [proceedings

Multiple sources of esterase enzymes in the crop juice ofCepaea (Mollusca: Helicidae)

Previous workers have (a) compared pulmonate crop juice and digestive gland extracts and found a close similarity in the enzymic complements from these two sources, and (b) located specific enzymes within the various cell types of the digestive gland. The digestive gland seems to be the major source of extracellular enzymes but what is not clear is which of the enzymes associated with particular intracellular structures are actively secreted into the crop juice. The present study has used polyacrylamide disc gel electrophoresis to investigate the digestive gland and crop juice esterases ofCepaea nemoralis andC. hortensis. It appears that only some of the digestive gland esterases are specifically secreted. The variation shown in crop juice esterases suggests three independent sources in the digestive gland. Less detailed studies ofHelix aspersa andArianta arbustorum also indicate multiple sources of extracellular esterases.

Characterization of a rifampin-resistant, conditional asporogenous mutant of Bacillus subtilis.

A rifampin-resistant, conditionally asporgoenous mutant of Bacillus subtilis was isolated that sporulates poorly in Sterlini-Mandelstam sporulation medium, but that sporulates normally in modified Difco sporulation medium. Rifampin-resistant (Rif-r) and conditional asporogenous (Spo-c) phenotypes co-transformed at 100% frequency. Preliminary genetic studies indicated the Rif-r trait to lie between cysA14 and ery, a locus (rnp) common to Rif-r mutants. Ribonucleic acid polymerase from strains bearing this mutation was found to be rifampin resistant in vitro. The loss of ability to sporulate in Sterlini-Mandelstam medium was found to be corrected, to a large extent, by addition to the medium of arginine, methionine, valine, and isoleucine. Several other amino acids had small effects, whereas others had no effect at all. The restorative effect is approximately additive. Growth studies indicated that Rif-r strains grew more rapidly than the corresponding parent in minimal medium at temperatures higher than 37 C. Addition of certain amino acids to the medium resulted in identical growth rates at these temperatures. Extracellular protease and esterase activities of the Rif-r Spo-c mutant were normal. A slight difference was found in the heat sensitivity of partially purified ribonucleic acid polymerase preparations of this mutant compared to the wild type.

Properties of a stable cell-free esterase from soil.

The properties of a stable, extracellular phenyl esterase which hydrolyzes the organophosphorus insecticide, malathion, to its monoacid were investigated following its isolation from soil by 0.2 N alkali extraction and 560-fold purification by MnC12 treatment, protamine sulfate treatment, and QAE Sephadex A-50 chromatography. Phosphonate and phenyl thiophosphate anticholinesterase insecticides were potent competitive inhibitors of soil esterase activity. Inhibi- tion was also observed with mono- and dithiols, but not with diisopropyl fluorophosphate or sulfhydrol compounds. The esterase was not susceptible to enzymatic proteolysis nor A heat-labile component has been isolated from soil which degrades the insecticide, malathion (diethyl mercaptosuc- cinate, S-ester with 0,O-dimethyl phosphorodithioate), to its monoacid, and evidence was presented that the substance is a stable, cell-free enzyme (Getzin and Rosefield, 1968, 1971). It was partially purified by procedures employed for isolating proteins and exhibited typical Michaelis-Menten kinetics. It was electrophoretic, filterable, heat-labile, nondialyzable, and susceptible to denaturation by acid and alkali. Its exis- tence as a stable, cell-free enzyme was postulated from evi- dence based upon the persistence and adsorptive character- istics of the partially purified material in soil. Soil enzymes must possess certain characteristics to ensure their existence in the cell-free state for extended periods. The malathion esterase has some of these properties (Getzin and Rosefield, 1971). It is not easily destroyed by heat, resists microbial attack, loses little or no activity upon prolonged storage, and is resistant to desiccation in soil. Perhaps most significant, it withstands the comparatively drastic alkali treatment necessary for freeing it from soil and thus enables one to examine its properties in vitro. The present investiga- tions were designed to further purify and characterize the enzyme and to examine some of the properties that contribute to its unusual stability in soil. Experimental Section Materials. Chehalis clay loam (pH 5.5-6.0) was collected from a cultivated area in western Washington and used as a source of the enzyme. It contained 8 z organic matter and 30 z clay. (I4C)Malathion (14.0 pCi/mg), labeled at the 2 and 3 positions of the succinyl moiety, was purchased from Amer- sham/Searle Corp ., Chicago, Ill. Nonradioactive malathion (98.5 purity) and malaoxon were obtained from American

Extracellular esterases of group A streptococci.

Methods were devised to prepare and estimate quantitatively the extracellular esterases of group A streptococci (STE). Two types of esterase preparations were prepared, corresponding to Stock and Lynn's serotype I (STE I) and II (STE II). The former was prepared from Streptococcus pyogenes strain SS379 (group A, type 40), and the latter from S. pyogenes strain 69882 (group A, type 49). Effects of cupric acetate, sera of various animals, and rabbit antisera to STE I and II on the activities of STE were tested. Cupric acetate added in substrate solution inhibited the activities of STE according to the concentration of cupric acetate. Sera of various animals (calf, guinea pig, horse, sheep, and pig) stimulated the activities of STE and protected them from the inhibitory effect of cupric acetate. Among the sera of various animals, horse serum gave the most potent activating and protecting effect, and was the serum from which the effective factor (horse serum-activating factor, HAF) was extracted by precipitation with ammonium sulfate. STE I was not stimulated by serum or HAF as markedly as STE II, but both enzymes were protected likewise by serum or HAF from the inhibition of cupric acetate. Antibodies to STE I and II were prepared in rabbits. Their effects on STE resembled that of HAF, but differed from the latter in immunological specificity. Activities of STE were stimulated and protected more markedly by homologous antiserum than by heterologous antiserum or normal rabbit serum. Applying suitable conditions, we defined the potency of STE and differentiated antibodies to STE I and II and normal serum quantitatively.

Characterization of haemolytic enterococci isolated from oral infections.

Ninetytwo strains of haemolytic enterococci were isolated from patients with different oral infections — apical periodontitis and pulpitis — and identified by physiological, biochemical and serological tests. AH strains produced at least one haemolytic toxin which lysed rabbit erythrocytes. Most strains produced extracellular esterase, protease, and a bacteriolytic enzyme. No lecithinase, lipase, DNAse, amylase or staphylolytic enzyme were observed in the strains investigated.

Purification and properties of a phenol carboxylic acid acyl esterase from Aspergillus flavus.

Aspergillus flavus produces an extracellular esterase that hydrolyses phenolic carboxylic acid acyl esters. An assay based upon the measurement of the rate of release of phloroglucinol on hydrolysis of the ester of phloroglucinol and protocatechuic acid is described. The most active preparation hydrolyzed 30.8 μmoles of substrate per minute per milligram of protein and was active against a wide range of esters of meta and para hydroxybenzoic acid derivatives.The enzyme was isolated as a homogeneous protein, as judged by ultracentrifugation and by electrophoresis and had an isoelectric point of pH 4.45. The molecular weight was determined as 166 000. The enzyme is a glycoprotein containing 42.8% carbohydrate and the amino acid composition is described.

A study of the esterases and their function in Candida lipolytica, Aspergillus niger and a yeast-like fungus.

SUMMARY: Esterases, determined by polyacrylamide gel electrophoresis, were present when Candida lipolytica was grown in a liquid, shaken, glucose-mineral salts medium. Intracellular esterase activity increased during growth, but extracellular esterase activity was small and increased only marginally. Esterases were not detected in organisms grown on solid glucose-mineral salts medium, but were present when glycerol tributyrin replaced glucose. At the onset of asexual sporulation in a yeast-like fungus, three new esterases occurred. Intracellular esterase activity increased, intracellular lipid utilization occurred, and the respiratory quotient decreased. No extracellular esterase activity was detected. Esterases were only detected in Aspergillus niger at late stages of conidiation when intracellular lipid decreased. Esterase activity was not detected in the mitochondria or in the cell-free growth medium. Esterases of all organisms tested hydrolysed glycerol tributyrin and were arbitrarily classified as lipases; intracellular lipid decreased with increase in esterase activity function. Esterase and profile changes may reflect a role of lipids in sporulation and physiological ageing.

Extracellular Esterases of Streptococci and the Distribution of Specific Antibodies in Human Sera of Various Age Groups

Summary Most of the streptococci representative of Lancefield Groups A through O produced an extracellular carboxylic acid esterase active against β-naphthyl acetate. No esterase activity was found in organisms of Groups D and N. Group K strains were not examined. The esterases could be differentiated into five distinct immunologic types based on reactions of identity or non-identity in immunodiffusion with normal adult human sera. A few strains produced esterases that did not react with the human sera in these immunologic tests. The distribution of antibodies to the five esterases was determined in the sera of infants, children and adults. Antibodies to the esterase E-IV, obtained from animal Group C strains, were rarely found. Antibodies to the other four esterases, E-I, E-II, E-III, and E-V, were present in the sera of newborns as frequently as they were in adults. Presumably these were antibodies obtained from the mother by placental transfer. Infants produced antibodies to these esterases with increasing frequency after the first year of age. The incidence of antibodies to these esterases in children in the 9- and 10-year-old age groups was similar to that observed in adults. The occurrence of antibodies to esterases E-III and E-V obtained from Group B and Group L streptococci, respectively, is contrary to present epidemiologic data pertaining to human infection with these organisms. A cross-reacting antigenic stimulus has not been demonstrated.

Ester-splitting activity of the electroplax

1.1. The hydrolysis of acetylcholine, dl-acetyl-β-methylcholine, ethyl chloroacetate, triacetin and butyrylcholine by intact and homogenized isolated single cells and by the connective tissue between electroplax has been tested. Some connective tissue remains attached to the electroplax; a correction for this extracellular esterase was therefore applied to evaluate esterase activity of the electroplax proper.2.2. The electroplax enzyme displays the characteristics of acetylcholinesterase. The connective tissue enzyme has neither the characteristics of acetylcholinesterase, human-serum cholinesterase, aliesterase nor arylesterase. In some respects, however, it resembles the cholinesterase of certain piscine plasmas.3.3. Hydrolysis of low concentrations of acetylcholine by intact cells is mainly by acetylcholinesterase of the electroplax, whereas high concentrations of acetylcholine are mainly hydrolyzed by the connective tissue esterase. Both enzymes are inhibited by physostigmine. Ethyl chloroacetate is hydrolyzed by at least 2 enzymes in the electroplax, only one of which is inhibited by physostigmine.4.4. There is a strong permeability barrier to the penetration of acetylcholine to the interior enzyme of the intact electroplax. This barrier is less strong for dl-acetyl-β-methylcholine, ethyl chloroacetate, triacetin and butyrylcholine.5.5. Concentrations of physostigmine which block electrical activity markedly depress acetylcholine hydrolysis. Tetracaine even in much higher concentrations than required to block electrical activity only slightly inhibits acetylcholine hydrolysis. Inhibition by neostigmine is intermediate between that of tetracaine and physostigmine.

Electrophoretic mobility and detection of haemolytic activity of streptolysins O and S in agar-gel.

Extracellular Esterase of Group a Streptococci : Electrophoretic Mobility and Detection of Haemolytic Activity of Streptolysins O and S in Agar-Gel

Extracellular Esterase of Group A Streptococci : Esterase in Extracellular Concentrates of Group A Streptococci and the Homologous Antibody

Extracellular Esterase of Group A Streptococci : Esterase in Extracellular Concentrates of Group A Streptococci and the Homologous Antibody

Distribution of esterase in gastric mucosa.

Sections of frozen-dried stomach mucosa of the rabbit cut at various levels from the surface were analyzed for esterase activity in relation to the proportions of cell types present. Aside from the fraction attributable to extracellular esterase all the esterase activity appears to be in proportion to the numbers of foveolar and neck mucous cells present in the sample.