Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) in human amniotic fluid were estimated in the presence of selective inhibitors. Amniotic fluid cholinesterases (mixture of acetylcholinesterase and butyrylcholinesterase) purified by procainamide-Sepharose affinity chromatography exhibited aryl acylamidase activity which was sensitive to serotonin inhibition (a property of aryl acylamidases associated with both acetyl- and butyrylcholinesterases) and tyramine activation (shown exclusively by aryl acylamidase associated with butyrylcholinesterase). Tyramine activation was unaffected in the presence of the selective acetylcholinesterase inhibitor BW284C51 whereas it was abolished in the presence of the selective butyrylcholinesterase inhibitor ethopropazine, suggesting the presence of both types of aryl acylamidases in amniotic fluid, one associated with acetylcholinesterase and the other associated with butyrylcholinesterase. Butyrylcholinesterase and the associated aryl acylamidase activity in the affinity purified enzyme was selectively immunoprecipitated by a polyclonal antibody raised against human serum butyrylcholinesterase. Estimation of the activity ratio of acetylcholinesterase to butyrylcholinesterase in a few samples of amniotic fluid showed that this could vary depending on the butyrylcholinesterase arising from contaminating blood in the samples. Gel electrophoresis under non-denaturing conditions and enzyme staining showed that butyrylcholinesterase band was detectable on the gel in all the samples whereas acetylcholinesterase band was below detectable levels in normal samples but visible in samples from pregnancies of neural tube defect fetuses. It is suggested that the use of selective cholinesterase inhibitors along with gel electrophoresis and immunoprecipitation studies may be useful in the assessment of cholinesterase activities in human amniotic fluid.
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PMID:Cholinesterases exhibiting aryl acylamidase activity in human amniotic fluid. 134 16

Purified human serum butyrylcholinesterase (approximately 90-kDa subunit) is known to exhibit aryl acylamidase and peptidase activity. Limited alpha-chymotrypsin digestion of the purified butyrylcholinesterase gave three major protein fragments of approximately 50 kDa, approximately 21 kDa and approximately 20 kDa. In our earlier studies [Rao and Balasubramanian (1989) Eur. J. Biochem. 179, 639-644] we characterized the approximately 20-kDa fragment and showed that it exhibited both butyrylcholinesterase and aryl acylamidase activities. In the present studies the approximately 50-kDa fragment is characterized. This fragment, after isolation by Sephadex G-75 chromatography from a chymotryptic digest of purified butyrylcholinesterase, exhibited only peptidase activity and was devoid of cholinesterase and aryl acylamidase activities. It could bind to a column of Ricinus communis agglutinin bound to Sepharose, indicating its glycosylated nature and the presence of galactose. The peptidase activity in the approximately 50-kDa fragment could be immuno-precipitated by a polyclonal antibody raised against purified butyrylcholinesterase. SDS-gel electrophoresis of this fragment isolated by R. communis agglutinin-Sepharose and Sephadex G-75 chromatography showed a protein band of approximately 50 kDa by silver staining. Amino-terminal sequence analysis of the approximately 50-kDa fragment gave the sequence of Gly-Pro-Thr-Val-Asp which corresponded to amino acid residues 291-295 in the butyrylcholinesterase sequence [Lockridge et al. (1987) J. Biol. Chem. 262, 549-557]. The combined results suggested that alpha-chymotrypsin digestion of human serum butyrylcholinesterase resulted in the formation of a approximately 20-kDa fragment exhibiting both cholinesterase and aryl acylamidase activities and a approximately 50-kDa fragment exhibiting only peptidase activity.
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PMID:Localization of the peptidase activity of human serum butyrylcholinesterase in a approximately 50-kDa fragment obtained by limited alpha-chymotrypsin digestion. 233 89

Human cerebrospinal fluid contained both acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) and they were estimated in the presence of selective inhibitors. Butyrylcholinesterase of human cerebrospinal fluid was similar to human serum butyrylcholinesterase in its electrophoretic mobility, glycoprotein nature and tyramine activation of the aryl acylamidase (EC 3.5.1.13) activity exhibited by butyrylcholinesterase. Moreover antibody raised against human serum purified butyrylcholinesterase could completely immunoprecipitate butyrylcholinesterase from human cerebrospinal fluid without affecting acetylcholinesterase. It is suggested that a useful method for the precise determination of acetylcholinesterase in human cerebrospinal fluid would be removal of butyrylcholinesterase by immunoprecipitation using antibody raised against human serum butyrylcholinesterase.
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PMID:Human cerebrospinal fluid acetylcholinesterase and butyrylcholinesterase. Evidence for identity between the serum and cerebrospinal fluid butyrylcholinesterase. 279 3

Highly purified human serum cholinesterase (EC 3.1.1.8, also known as pseudocholinesterase and butyrylcholinesterase) had peptidase activity toward substance P. Digestion of substance P was monitored by high performance liquid chromatography, which separated three product peptides. The cleavages occurred sequentially. The first peptide to appear as Arg1-Pro2. The Km for this hydrolysis was 0.3 mM; maximum activity was 7.9 nmol min-1 mg-1 of protein, which corresponded to a turnover number of 0.6 min-1. A second cleavage yielded Lys3-Pro4. A third cleavage occurred at the C-terminal, where the amide was removed from Met11 to yield a peptide containing residues 5-11. Both the peptidase and esterase activities of the enzyme were completely inhibited by the anticholinesterase agent, diisopropylfluorophosphate. Substance P inhibited the hydrolysis of benzoylcholine (a good ester substrate) with a KI of 0.17 mM, indicating that substance P interacted with cholinesterase rather than with a trace contaminant. Peptidase and amidase activities for serum cholinesterase are novel activities for this enzyme. It was demonstrated previously that the related enzyme acetylcholinesterase (EC 3.1.1.7) catalyzed the hydrolysis of substance P, but at entirely different cleavage sites from those reported in the present work. Since butyrylcholinesterase is present in brain and muscle, as well as in serum, it may be involved in the physiological regulation of substance P.
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PMID:Substance P hydrolysis by human serum cholinesterase. 617 30

Cholinesterases (acetylcholinesterase and butyrylcholinesterase) exhibit additional catalytic activities apart from their well-known action in hydrolyzing choline esters. An amine-sensitive aryl acylamidase activity is exhibited by both acetyl- and butyrylcholinesterases. A metallocarboxypeptidase-like activity is found associated with both acetyl- and butyrylcholinesterases. The peptidase activity exhibited by butyrylcholinesterase was located in a 50-kDa COOH-terminal fragment. Acetylcholinesterase is implicated in noncholinergic functions in the substantia nigra. A relationship between tumorigenesis, cell differentiation, and cholinesterases has been speculated. The sequence similarities between different esterases, lipases, thyroglobulin, cell adhesion proteins, and cholinesterases would make it appear that cholinesterases are capable of exhibiting more than one biological activity and their functions are wider than what is hitherto known.
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PMID:Noncholinergic functions of cholinesterases. 822 8

Purified human serum butyrylcholinesterase, which exhibits cholinesterase, aryl acylamidase, and peptidase activities, was cross-reacted with two different monoclonal antibodies raised against human serum butyrylcholinesterase. All three activities were immunoprecipitable at different dilutions of the two monoclonal antibodies. At the highest concentration of the antibodies used, nearly 100% of all three activities were precipitated, and could be recovered to 90-95% in the immunoprecipitate. The peptidase activity exhibited by the purified butyrylcholinesterase was further characterized using both Phe-Leu and Leu-enkephalin as substrates. The pH optimum of the peptidase was in the range of 7.5-9.5 and the divalent cations Co2+, Mn2+, and Zn2+ stimulated its activity. EDTA and other metal complexing agents inhibited its activity. Thiol agents and -SH group modifiers had no effect. The serine protease inhibitors, diisopropylfluorophosphate and phenyl methyl sulfonyl fluoride, did not inhibit. When histidine residues in the enzyme were modified by diethylpyrocarbonate, the peptidase activity was not affected, but the stimulatory effect of Co2+, Mn2+, and Zn2+ disappeared, suggesting the involvement of histidine residues in metal ion binding. These general characteristics of the peptidase activity were also exhibited by a 50 kD fragment obtained by limited alpha-chymotrypsin digestion of purified butyrylcholinesterase. Under all assay conditions, the peptidase released the two amino acids, leucine and phenylalanine, from the carboxy terminus of Leu-enkephalin as verified by paper chromatography and HPLC analysis. The results suggested that the peptidase behaved like a serine, cysteine, thiol-independent metallopeptidase.
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PMID:The peptidase activity of human serum butyrylcholinesterase: studies using monoclonal antibodies and characterization of the peptidase. 842 27

The potency of a series of anticholinesterase (anti-ChE) agents and serotonin-related amines as inhibitors of the aryl acylamidase (AAA) activity associated with electric eel acetylcholinesterase (AChE) (EC 3.1.1.7) and horse serum butyrylcholinesterase (BuChE) (EC 3.1.1.8) was examined and compared with the potency of the same compounds as ChE inhibitors. Neostigmine, physostigmine, BW 284C51, (+/-)-huperzine A, E2020, tacrine, edrophonium and heptyl-physostigmine were, in that order, the most potent in inhibiting eel AChE-associated AAA activity, their inhibitor constant (Ki) values being in the range 0.02-0.37 microM. The rank order of the same compounds as AChE inhibitors basically paralleled that of AAA, although they were in general stronger on AChE (Ki = 0.001-0.05). The peripheral anionic site inhibitors propidium and gallamine were inactive on AChE-associated AAA. Serotonin and its derivatives were slightly stronger on AAA (Ki = 7.5-30 microM) than on AChE (Ki = 20-140 microM). Tacrine (IC50 = 0.03 microM), diisopropylfluorophosphate (IC50 = 0.04 microM), heptyl-physostigmine (IC50 = 0.11 microM), physostigmine (IC50 = 0.15 microM) and tetra-iso-propylpyrophosphoramide (iso-OMPA) (IC50 = 0.75 microM) were the most potent in inhibiting horse serum BuChE-associated AAA activity. Serotonin and related amines were very weak on BuChE-associated AAA activity. These results indicate that the inhibitory potencies of the active site anti-ChE agents on the AAA activity associated with eel AChE and horse serum BuChE are closely correlated with their action on the respective ChE. In addition, the efficacy of tacrine, E2020, heptyl-physostigmine and (+/-)-huperzine A in the treatment of Alzheimer's disease is unlikely to be related to the action of these drugs on ChE-associated AAA.
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PMID:Inhibition of cholinesterase-associated aryl acylamidase activity by anticholinesterase agents: focus on drugs potentially effective in Alzheimer's disease. 963 11

Cholinesterases exhibit functions apart from their esterase activity. We have demonstrated an aryl acylamidase and a zinc stimulated metallocarboxypeptidase activity in human serum butyrylcholinesterase. To establish the presence of zinc binding sites in the enzyme we examined the effect of metal chelators on its catalytic activities. The metal chelators 1,10-phenanthroline and N,N,N',N'-tetrakis (2-pyridyl methyl)ethylene diamine (TPEN) inhibited all the three catalytic activities in the enzyme. However, EDTA inhibited the peptidase activity exclusively without affecting the cholinesterase and aryl acylamidase activities. The catalytic activities were recovered upon removal of the chelator by Sephadex G-25 chromatography. Pre-treatment of the enzyme with any one of the three chelators resulted in the binding of the enzyme to a zinc-Sepharose column or to 65Zn2+. Histidine modification of the enzyme pretreated with chelators resulted in abolition of 65Zn2+ binding and zinc-Sepharose binding. Whereas the binding studies demonstrated removal of a metal from a Zn2+ binding site, attempts to remove the metal responsible for catalytic activity were unsuccessful. Atomic absorption spectroscopy indicated approximately 2.5 mol of zinc per mol of enzyme before treatment with EDTA and 1 mol zinc per mol enzyme after EDTA treatment. The results indicate that there are at least two metal binding sites on butyrycholinesterase. The presence of two HXXE...H sequences in butyrylcholinesterase supports these findings. Our studies implicate a zinc dependent metallocarboxypeptidase activity in the non-cholinergic functions of butyrylcholinesterase.
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PMID:Selective inactivation of butyrylcholinesterase with metal chelators suggests there is more than one metal binding site. 969 26

Several side activities have been attributed to butyrylcholinesterase (BChE), including aryl acylamidase (AAA) activity, which is an amidase-like activity with unknown physiological function splitting the artificial substrate o-nitroacetanilide. For avians, extensive developmental data have pointed to neurogenetic functions of BChE, however, a possible AAA activity of BChE has not been studied. In this study, we first compare the relative levels of AAA exhibited by BChE in whole sera from chick, fetal calves (FCS) and horse. Remarkably, FCS exhibits a 400-fold higher ratio of AAA/BChE than horse and 80-fold higher than chick serum. We then show that an immunoisolated preparation of BChE from chicken serum presents significant activity for AAA. Both in sera and with the purified enzyme, the AAA activity is fully inhibited by anticholinesterase drugs, showing that AAA activity is exclusively conveyed by the BChE molecule. Noticeably, AAA inhibition even occurs at lower drug concentrations than that of BChE activity itself. Moreover, AAA is sensitive to serotonin. These data indicate that (1) AAA is a general feature of serum BChE of vertebrates including avians, (2) AAA is effectively inhibited by cholinergic and serotonergic agents, and (3) AAA may have a developmental role, since it is much pronounced in a serum from fetal animals. Functionally, deamination of neuropeptides, a link between cholinergic and serotonergic neurotransmitter systems, and roles in lipoprotein metabolism could be relevant.
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PMID:Aryl acylamidase activity exhibited by butyrylcholinesterase is higher in chick than in horse, but much lower than in fetal calf serum. 1021 80

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) from vertebrates, other than their predominant acylcholine hydrolase (esterase) activity, display a genuine aryl acylamidase activity (AAA) capable of hydrolyzing the synthetic substrate o-nitroacetanilide to o-nitroaniline. This AAA activity is strongly inhibited by classical cholinesterase (ChE) inhibitors. In the present study, benzalkonium chloride (BAC), a cationic detergent widely used as a preservative in pharmaceutical preparations, has been shown to distinctly modulate the esterase and AAA activities of BChEs. The detergent BAC was able to inhibit the esterase activity of human serum and horse serum BChEs and AChEs from electric eel and human erythrocyte. The remarkable property of BAC was its ability to profoundly activate the AAA activity of human serum and horse serum BChEs but not the AAA activity of AChEs. Thus BAC seem to preferentially activate the AAA activity of BChEs alone. Results of the study using the ChE active site-specific inhibitor diisopropyl phosphorofluoridate indicated that BAC binds to the active site of ChEs. Furthermore, studies using a structural homolog of BAC indicated that the alkyl group of BAC is essential not only for its interaction with ChEs but also for its distinct effect on the esterase and AAA activities of BChEs. This is the first report of a compound that inhibits the esterase activity, while simultaneously activating the AAA activity, of BChEs. Copyright 2000 Academic Press.
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PMID:Distinct Effect of Benzalkonium Chloride on the Esterase and Aryl Acylamidase Activities of Butyrylcholinesterase. 1103 85


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