Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sialate 9(4)-O-acetylesterases (EC 3.1.1.53) have been isolated from equine liver, bovine brain and influenza C virus. In this latter case, the esterase represents the receptor-destroying enzyme of the virus. The kinetic properties of these enzymes were determined with Neu5,9Ac2 and in part with 4-methylumbelliferyl acetate and Neu5,9Ac2-lactose. The Km values vary between 0.13 and 24 mM and the Vmax values from 0.55 to 11 U/mg of protein. The pH optima are in the range of 7.4-8.5, the molecular masses at 56,500 and 88,000 Da. In addition to a fast hydrolysis found for aromatic acetates, such as 4-methylumbelliferyl acetate or 4-nitrophenyl acetate, N-acetyl-9-O-acetylneuraminic acid is de-O-acetylated at the highest relative rate. Other substituents at the 9-position, such as lactoyl residues, or acetyl groups at other positions within the side chain are not hydrolyzed. Neu4,5Ac2, however, is a substrate for all 3 enzymes. The hydrolysis rates of this ester function, which renders sialic acids resistant to the action of sialidases, vary from 3 to 100% relative to Neu5,9Ac2. Whereas Neu5,9Ac2-lactose is hydrolyzed by the bovine and viral esterases, other O-acetylated sialic acids in glycoconjugates are only attacked by the enzyme from influenza C virus and not by that from bovine brain. The esterase from horse liver also releases 4-O-acetyl groups from equine submandibular gland mucin. By incubation with appropriate substrates and inhibition studies, carboxylesterase, amidase and choline esterase activities were excluded, as well as the cleavage of other acyls, e.g., butyryl groups. Thus, the enzymes investigated belong to the acetylesterases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sialate O-acetylesterases: key enzymes in sialic acid catabolism. 314 20

As the present classification (19) of Clostridium sordellii and C. bifermentans is based on properties which are not conclusive for most of our strains, we investigated 80 strains from various origin of this group regarding 30 selected properties. Four of these properties were correlative and therefore particularly important for a distinct differentiation of the strains investigated: urease activity (U), growth inhibition by 1% mannose (M), arginine deaminase activity (A), and sialidase (EC 3.2.1.18) activity (S). Concerning these four characters three clusters were formed: cluster I was positive for U, M, A, and S and comprised 36 strains including C. sordellii type strain (ATCC 9714T); cluster II was positive for M and S and negative for U and A and comprised twelve strains including strain ATCC 35392; and cluster III was positive for A and negative for U, M, and S and comprised 32 strains including C. bifermentans type strain (ATCC 638T). Only two of the correlative properties (U and S, U and A, A and M, or A and S) needed to be tested to determine the affiliation of any strain of the C. sordellii/bifermentans group to one of the three clusters. Clusters I and II, representing two phenotypes of C. sordellii, can now clearly be distinguished from C. bifermentans. Sialidase formed by cluster I and II strains was inhibited by antibodies produced against cluster I strain sialidase. No cross reaction was found with other clostridial sialidases. Pathogenicity, hitherto considered as one of the distinctive properties of C. sordellii and C. bifermentans, was found with various strains of all the three clusters. Therefore, in the case of an infection caused by these two species, care should be taken as to the pathogenicity especially of C. bifermentans and treatment should be accordingly.
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PMID:Correlative properties for a differentiation of two Clostridium sordellii phenotypes and their distinction from Clostridium bifermentans. 391 62

The importance of viridans streptococci as agents of serious extra-oral diseases, including endocarditis, is now recognized. We have tested the hypothesis that the ability to utilize sialic acid as a nutrient source may play a role in the proliferation of these organisms. The type strains of the 15 presently recognized species of viridans streptococci and two clinical isolates-S. oralis (AR3), isolated from a patient with infective endocarditis, and S. intermedius (UNS35), a brain abscess isolate-were studied for their ability to utilize sialic acid. Only S. oralis, S. sanguis, S. gordonii, S. mitis ("oralis group") S. intermedius, S. anginosus, S. constellatus ("milleri group"), and S. defectivus ("nutritionally variant group") were able to use sialic acid (N-acetylneuraminic acid) efficiently as a sole carbon source. Formate, acetate, and ethanol were produced as the major metabolic end-products of sialic acid metabolism, while corresponding glucose-grown cultures produced lactate as the major metabolic end-product. Utilization of sialic acid was independent of the production of sialidase. Cell-free extracts of sialic acid-grown cultures expressed elevated levels of N-acetylneuraminate pyruvate-lyase (NPL; the first enzyme in the intracellular catabolism of sialic acid) and N-acetylglucosamine-6-phosphate (GlcNAc-6-P) deacetylase and glucosamine-6-phosphate (GlcN-6-P) deaminase (enzymes involved in the intracellular catabolism of N-acetylglucosamine). These activities were repressed by growth in the presence of glucose. The intracellular fate of sialic acid, after cleavage by NPL into N-acetylmannosamine (ManNAc) and pyruvate, is uncertain, but the elevated levels of GlcNAc-6-P deacetylase and GlcN-6-P deaminase in sialic acid-grown cells suggest that phosphorylation and isomerization are possible steps in the metabolism of ManNAc to generate an intermediate common to the pathway of N-acetylglucosamine metabolism. The species of viridans streptococci that have the ability to utilize sialic acid are those most commonly associated with extra-oral diseases, and this ability is likely to play a role in the persistence and survival of these infecting organisms in vivo.
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PMID:Utilization of sialic acid by viridans streptococci. 890 24

Spontaneous in vitro hatching of human blastocysts starts with the formation of a tunnel through the zona pellucida (ZP) by cellular projections of trophoblast cells. Our aim was to identify the proteins that are upregulated in these initially hatching cells as compared to trophectoderm (TE) cells from blastocysts that had not yet hatched. Forty seven women that underwent assisted reproduction treatment donated their ICSI-derived polyploid blastocysts for the study. In polyploid blastocysts that started spontaneous hatching, hatched clusters of cells were collected from the outer side of the ZP. Liquid chromatography mass spectrometry was applied to determine the proteins that were upregulated in these cells as compared to TE cells obtained from inside the ZP. Whole non-hatched polyploid blastocysts were used as controls. Overall 1245 proteins were identified in all samples. Forty nine proteins were significantly upregulated in hatching cells and 17 in the TE cells. There was minimal overlap between hatching and TE samples; only serine protease inhibitors (SERPINS) and lipocalin were detected in both samples. Myosin and actin were highly upregulated in the hatching cells as well as paraoxonase, N-acetylmuramoyl alanine amidase, and SERPINS clade A and galectin. In the TE cells, gamma butyrobetaine dioxygenase, lupus La protein, sialidase, lysosomal Pro-X carboxypeptidase, phospholipase b, and SERPINS clade B and A were among the most highly upregulated proteins. These findings may contribute to the basic knowledge of the molecular behavior of the specific cells that actively perforate the glycoprotein matrix of the ZP.
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PMID:Spontaneous in vitro hatching of the human blastocyst: the proteomics of initially hatching cells. 3319 35