[Changes in serum leucine aminopeptidase activity during halothane anesthesia with and without thiopental administration].
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Abdomen↗
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Results for “LEUCINE AMINOPEPTIDASE”
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[Urinary excretion of leucine aminopeptidase after extracorporeal shock wave lithotripsy].
Extracorporeal shock-wave lithotripsy (ESWL) is the treatment of choice in the majority of urinary calculi. In experimental and clinical research it has been shown that the method has short-term deleterious effects on renal function. Several factors, such as urinary tract infection (UTI), the site of the stone, pre-existing renal abnormalities, the number and intensity of the shock waves may influence the extent of the damage. The aim of this study was to measure the excretion of the renal microsomal enzyme, leucinaminopeptidase (MLAP) as expression of renal damage following ESWL. Our study shows that there was a significant elevation in urinary excretion of MLAP immediately after ESWL, especially in patients with UTI. These results indicate that UTI may be one of the risk factors for aggravation of renal damage after ESWL. However, these changes are transient and expressed less than in patients with light renal trauma arising because of other external influence.
Adolescent↗
[Leucine aminopeptidase (LAP)].
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Female↗
[Interpretation of electron microscopic images of crystalline aggregates of leucine aminopeptidase].
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Crystallization↗
Release of alkaline phosphodiesterase I from rat kidney plasma membrane produced by the phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis.
The release of plasma-membrane-bound enzymes by phosphatidylinositol-specific phospholipase C obtained from Bacillus thuringiensis was investigated. Among the ectoenzymes of plasma membrane tested, alkaline phosphodiesterase I was released markedly from rat kidney cortex slices, in addition to alkaline phosphatase and 5'-nucleotidase. Other membrane-bound enzymes; alanine aminopeptidase, leucine aminopeptidase, dipeptidyl peptidase, leucine aminopeptidase, dipeptidyl peptidase IV, esterase and gamma-glutamyl transpeptidase could not be liberated from the treated slices. Alkaline phosphodiesterase I was released linearly from rat kidney slices with the concentration of phosphatidylinositol-specific phospholipase C, but little enzyme was released from rat liver slices. Alkaline phosphodiesterase I separated from kidney tissue with n-butanol still retained phosphatidylinositol and was transformed into a lower molecular weight form by phosphatidylinositol-specific phospholipase C. This suggests an important function for phosphatidylinositol in the binding of alkaline phosphodiesterase I to the plasma membrane of rat kidney cells. The alkaline phosphodiesterase I released from rat kidney had a molecular weight of about 240,000 and an isoelectric point (pI) of 5.4. The enzyme hydrolyzed the phosphodiester linkage of p-nitrophenyl-thymidine 5'-monophosphate at pH 8.9 and had a Km value of 0.3 mM. The enzyme was activated by Mg2+ and Ca2+, but was inhibited by EDTA. Strong inhibition took place on the addition of adenosine 5'-phosphosulfate or the nucleotide pyrophosphates, i.e., UDP-galactose and alpha, beta-methylene ATP.
Animals↗
Synthesis and structure activity relationships of novel non-peptidic metallo-aminopeptidase inhibitors.
Racemic derivatives of 3-amino-2-tetralone were synthesised and evaluated for their ability to inhibit metallo-aminopeptidase activities. New compounds substituted in position 2 by methyl ketone, substituted oximes or hydroxamic acids as well as heterocyclic derivatives were evaluated against representative members of zinc-dependent aminopeptidases: leucine aminopeptidase (E.C. 3.4.11.1), aminopeptidase-N (E.C. 3.4.11.2), Aeromonas proteolytica aminopeptidase (E.C. 3.4.11.10), and the aminopeptidase activity of leukotriene A(4) hydrolase (E.C. 3.3.2.6). Several compounds showed K(i) values in the low micromolar range against the 'one-zinc' aminopeptidases, while most of them were rather poor inhibitors of the 'two-zinc' enzymes. This interesting selectivity profile may guide the design of new, specific inhibitors of target mammalian aminopeptidases with one active site zinc.
Aeromonas↗
Pathway for degradation of peptides generated by proteasomes: a key role for thimet oligopeptidase and other metallopeptidases.
The degradation of cellular proteins by proteasomes generates peptides 2-24 residues long, which are hydrolyzed rapidly to amino acids. To define the final steps in this pathway and the responsible peptidases, we fractionated by size the peptides generated by proteasomes from beta-[14C]casein and studied in HeLa cell extracts the degradation of the 9-17 residue fraction and also of synthetic deca- and dodecapeptide libraries, because peptides of this size serve as precursors to MHC class I antigenic peptides. Their hydrolysis was followed by measuring the generation of smaller peptides or of new amino groups using fluorescamine. The 14C-labeled peptides released by 20 S proteasomes could not be degraded further by proteasomes. However, their degradation in the extracts and that of the peptide libraries was completely blocked by o-phenanthroline and thus required metallopeptidases. One such endopeptidase, thimet oligopeptidase (TOP), which was recently shown to degrade many antigenic precursors in the cytosol, was found to play a major role in degrading proteasome products. Inhibition or immunodepletion of TOP decreased their degradation and that of the peptide libraries by 30-50%. Pure TOP failed to degrade proteasome products 18-24 residues long but degraded the 9-17 residue fraction to peptides of 6-9 residues. When aminopeptidases in the cell extract were inhibited with bestatin, the 9-17 residue proteasome products were also converted to peptides of 6-9 residues, instead of smaller products. Accordingly, the cytosolic aminopeptidase, leucine aminopeptidase, could not degrade the 9-17 residue fraction but hydrolyzed the peptides generated by TOP to smaller products, recapitulating the process in cell extracts. Inactivation of both TOP and aminopeptidases blocked the degradation of proteasome products and peptide libraries nearly completely. Thus, degradation of most 9-17 residue proteasome products is initiated by endoproteolytic cleavages, primarily by TOP, and the resulting 6-9 residue fragments are further digested to amino acids by aminopeptidases.
Aminopeptidases↗
Rapid identification of Campylobacter pylori (C. pyloridis) by preformed enzymes.
Campylobacter pylori (C. pyloridis) is a fastidious organism found in the gastric mucosa associated with histological gastritis and peptic ulceration. A rapid identification scheme that detects the presence of preformed enzymes (Rosco Diagnostica, Taastrup, Denmark) was applied to clinical isolates of C. pylori. The isolates tested were a very homogeneous group. They all produced oxidase, catalase, urease, alkaline phosphatase, gamma-glutamyl aminopeptidase, leucine aminopeptidase, and DNase. None produced any of 44 other enzymes tested. No other campylobacter strains produced gamma-glutamyl aminopeptidase, except the six strains of Campylobacter jejuni biotype 2. Different results were obtained with similar substrates produced by other manufacturers, probably due to small substrate differences. These tests are useful for the rapid identification of C. pylori but would be unhelpful in any biotyping scheme. They can also be used to help differentiate other groups within the genus Campylobacter.
Alkaline Phosphatase↗
Effect of hydrocortisone on the activity of some lysosomal enzymes in mice.
OBJECTIVES: Changes in the activity of cathepsin D and L, alanine aminopeptidase, leucine aminopeptidase, N-acetyl-beta-glucosaminidase, lysosomal arylesterase and lysosomal lipase in the liver and kidney of unselected and selected mice, subjected to 7.5 mg/kg b.w. of hydrocortisone injection for 4 and 8 days. METHODS: The homogenates of the liver and kidney were subjected to differentiated centrifuging and determination of studied enzymes. RESULTS: Injection of hydrocortisone caused an increase in the activity of all investigated lysosomal enzymes in the liver and kidney of mice. CONCLUSION: The reactions of selected mice were stronger in comparison with unselected ones. The highest increase in the activity investigated enzymes was observed after 8 days of hydrocortisone injection.
Acetylglucosaminidase↗
Histochemical observations on the taste buds of the marmosets (Callithrix jacchus and Callithrix penicillata).
The epithelial cells in the taste buds of C. jacchus and C. penicillata show a moderate amount of ribonucleic acid an a concentration of a PAS-positive diastase-resistant material at their apical part. These cells are devoid of UDPG-GT, phosphorylases, G-6-PA, alanyl aminopeptidase, leucine aminopeptidase, cholinesterase and MAO; they present a weak reaction of F-1, 6-P Ald, LDH, SDH, MDH, cytochrome oxidase, beta-OHBDH, nonspecific esterase and acid phosphatase and a stronger reaction to ADH, NADPH2-TR, ATPases, alpha-GPDH, alkaline phosphatase, 5-nucleotidase and GDH. Although some enzymes (alkaline phosphatase, 5-nucleotidase and ATPases) have an almost uniform reactivity by the several taste buds, the other ones react with a lesser intensity in the smaller uniform reactivity by the several taste buds, the other ones react with a lesser intensity in the smaller taste buds of the fungiform papillae. As a rule the apical part of the cells shows a stronger enzymatic reactivity. The taste buds of the marmosets are penetrated by acetylcholinesterase positive nerve fibers whereas the autonomic ganglia in the connective tissue contain both-acetyl and butyrylcholinesterase.
Adenosine Triphosphatases↗
The function and morphology of the liver in porphyria cutanea tarda.
The aminopyrine breath test, postprandial serum bile acids, and routine liver tests were assessed as indicators of liver dysfunction in 38 patients with porphyria cutanea tarda. In 17 patients needle biopsy specimens of the liver were obtained. Bile acids were increased in almost all the patients studied (97%) but impairment of aminopyrine demethylation was found in only 45%. More than 50% of cases had elevated activities of serum alanine aminopeptidase, leucine aminopeptidase, gammaglutamyl transpeptidase (GGTP), and alanine aminotransferase (ALAT). All liver biopsy specimens showed fluorescence characteristic of porphyrins. Histologic examination of biopsy material revealed cellular lesions in all cases, the most common pathological findings being fatty degeneration of varying degree and iron accumulation. The most frequent electronmicroscopic changes in the liver were fat droplets, granules containing bile material, and siderosomes in the cytoplasm of hepatocytes. However, there was no evident relationship between morphological and functional liver changes.
Adult↗
Histochemical differences between the major salivary glands of the marmosets (Callithrix jacchus and Callithrix penicillata).
Histoenzymologic differences between the parotid, paramandibular and submandibular glands were studied in six Callithrix jacchus (four males and two females) and four Callithrix penicillata (three males and one female). The acinous cells of the paramandibular glands showed a stronger reactivity for the diaphorases (NADH2-TR and NADPH2-TR) and for a certain group of enzymes of the carbohydrate metabolism (F-1-6P Ald, LDH, ADH, G-6-PDH and 6-PGDH), lipid metabolism (alpha-GPDH, beta-OHBDH, alkaline phosphatase and acid phosphatase), protein metabolism (alanyl aminopeptidase, leucine aminopeptidase and GDH) and respiratory chain (cris-aconitase and ICDH). The nonspecific esterase was more reactive in the basal part of of the mucous cells of the submandibular glands. Conversely, some enzymes of the respiratory chain (SDH, cytochrome oxidase and ATPases) showed a stronger reactivity in the serous cells of the parotid and submandibular glands. The paramandibular glands exhibited a lesser autonomic innervation than the parotid and submandibular.
Animals↗
Histochemical studies on the adrenal glands of the marmosets (Callithrix jacchus and Callithrix penicillata).
The histrochemistry of the adrenal glands was studied in four adult male marmosets (two Callithrix jacchus and two Callithrix penicillata). It was impossible to demonstrate any reactivity to UDPG-GT, ADH, alanyl aminopeptidase, leucine aminopeptidase, xilitol (NAD-dependent) dehydrogenase, beta-glucuronidase and aryl-sulfatase in these glands. Total phosphorylase was found in scattered cells of the glomerulosa and adjacent outer fasciculata of one C. penicillata. The dehydrogenases (LDH, G-6-PDH,6-PGDH, NADPH2-TR,ICDH,SDH,NADH2-TR, alpha-GPDH, beta-OHBDH) as well as the hydrolases (except alkaline phosphatase, ATPase, and acetylcholinesterase) showed a stonger reactivity in the cortical part. Some hydrolases (naphthol acetate esterase, acid phosphatase) and cytochrome oxidase were less reactive in the zona glomerulosa, where the dehydrogenases were more abundant. The outer fasciculata and the reticularis also showed a strong dehydrogenase reactivity.
Acid Phosphatase↗
alpha-Aminoboronic acid derivatives: effective inhibitors of aminopeptidases.
alpha-Aminoboronic acids and their derivatives have been synthesized as stable white solids. These compounds are effective inhibitors of human enkephalin degrading aminopeptidase, microsomal leucine aminopeptidase (EC 3.4.11.2), and cytosolic leucine aminopeptidase (EC 3.4.11.1) at micro- to nanomolar concentrations. The inhibition of cytosolic leucine aminopeptidase has been studied in some detail. Kinetic data correspond to the mechanism for biphasic slow-binding inhibition: E + I in equilibrium E.I in equilibrium E.I*, in which a rapid initial binding is followed by a slow transformation to a stable enzyme inhibitor complex. The initial and final binding constants are dependent on the nature of the side chain at the alpha-carbon atom but are independent of the protecting group on the boronic acid moiety and follow the trend for the hydrolysis of the corresponding amino acid amides. The first-order rate constant for the transformation of E.I to E.I* is similar for all four compounds studied. These data suggest that the slow-binding step represents the formation of tetrahedral boronate species from trigonal boronic acid.
Animals↗
Comparison of vaginal aminopeptidase enzymatic activities in various animals and in humans.
The specific enzymatic activity of four different aminopeptidases (aminopeptidase N, leucine aminopeptidase, aminopeptidase A and aminopeptidase B) in vaginal homogenates from rabbit, rat, guinea-pig, sheep and humans was compared. The purpose of the study was to find an appropriate animal model that can be used in degradation studies of protein and peptide drugs. Different substrates were used as the relative specific substrates for the determination of aminopeptidase enzymatic activity: 4-methoxy-2-naphthylamide of L-alanine for aminopeptidase N, 4-methoxy-2-naphthylamide of L-leucine for leucine aminopeptidase, 4-methoxy-2-naphthylamide of L-glutamic acid for aminopeptidase A and 4-methoxy-2-naphthylamide of L-arginine for aminopeptidase B. The vaginal aminopeptidase enzymatic activity of different species was determined spectrofluorometrically. The inhibition of aminopeptidase activity in the presence of bestatin and puromycin inhibitors was also investigated. The results showed the presence of aminopeptidase enzymatic activity in all vaginal homogenates in the order: sheep > guinea-pig > rabbit > or = human > or = rat. Based on the results of the hydrolysis and inhibition of the 4-methoxy-2-naphthylamide substrates, it was difficult to have an exact decision on the aminopeptidase type in the vaginal homogenates from the species studied. It was found that the aminopeptidase activity in rat, rabbit and humans was not statistically different. Therefore, we suggest that rats and rabbits could be used as model animals for vaginal enzymatic activity studies and for determination of the degradation of protein and peptide drugs in the vagina.
2-Naphthylamine↗
A case of rheumatoid arthritis with various enzyme-immunoglobulin complexes.
Several complexes of enzymes and immunoglobulins were detected at the same time in the serum of a patient with seropositive rheumatoid arthritis. The enzymes which were found to complex with immunoglobulins were lactate dehydrogenase, alkaline phosphatase (liver, bone, placental, and intestinal isoenzymes), amylase, cytosol leucine aminopeptidase, and microsomal leucine aminopeptidase. Reconstitution studies after papain or pepsin digestion showed that the association site of the enzymes was in the Fab portion of the immunoglobulin component. We found these complexes to be the result of an antibody-antigen reaction. The binding capacity of each enzyme was variable over the entire time course. The patient's immunoglobulins, complexed with lactate dehydrogenase or amylase, could not be reconstituted using alkaline phosphatase, cytosol leucine aminopeptidase, or microsomal leucine aminopeptidase in vitro. Therefore, this suggests that the immunoglobulins which bind to each enzyme are independent of each other.
Aged↗
A comparative study on the rectal aminopeptidase enzymatic activities of different species.
The aim of the present study was to compare the enzymatic activity of four different aminopeptidases (aminopeptidase N, leucine aminopeptidase, aminopeptidase A, aminopeptidase B) in rectal homogenates from different species: rabbit, rat, guinea-pig, sheep and human. Different substrates were used as the relative specific substrates for the determination of aminopeptidase enzymatic activity. For this purpose, 4-methoxy-2-naphthylamide of L-alanine for aminopeptidase N, 4-methoxy-2-naphthylamide of L-leucine for leucine aminopeptidase, 4-methoxy-2-naphthylamide of L-glutamic acid for aminopeptidase A and 4-methoxy-2-naphthylamide of L-arginine for aminopeptidase B were employed. The rectal aminopeptidase enzymatic activity was determined spectrofluorometrically. The inhibition of activity of aminopeptidase in the presence of bestatin and puromycin inhibitors was also investigated. The results showed the presence of aminopeptidase enzymatic activity in all rectal homogenates. Sheep and guinea-pig had the greatest aminopeptidase activity. The four aminopeptidase activities of rat and rabbit were not significantly different from each other. Human data was not evaluated statistically, due to insufficient sample. But the values of human data was close to those of the rabbit and rat values except for aminopeptidase A. Based on the data of the hydrolysis and inhibition of the 4-methoxy-2-naphthylamide substrates, it was rather difficult to determine the aminopeptidase type in the rectal homogenates of the species studied. It has been found that the aminopeptidase activities of rat and rabbit were not statistically different from each other and the human data were close to them.
Aminopeptidases↗
The oxytocinase subfamily of M1 aminopeptidases.
The placental leucine aminopeptidase (P-LAP), adipocyte-derived leucine aminopeptidase (A-LAP) and leukocyte-derived aminopeptidase (L-RAP) belong to one distinct group of the M1 family of amimopeptidases, which we term the "Oxytocinase subfamily". They share HEXXH(X)18E Zn-binding and GAMEN motifs essential for the enzymatic activities. Intracellular localization is the characteristic feature of the subfamily members. While P-LAP is translocated from intracellular vesicles to plasma membrane in a stimulus-dependent manner, both A-LAP and L-RAP are retained in the endoplasmic reticulum. They contain sequences necessary for the specific localization in the cell. It is getting evident that the subfamily members play important roles in the maintenance of homeostasis including maintenance of normal pregnancy, memory retention, blood pressure regulation and antigen presentation. In this review, current situation of this newly identified subfamily is summarized.
Amino Acid Sequence↗