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PubMedDate not supplied

Amidase and peptidase activities of polyclonal immunoglobulin G present in the sera of patients with rheumatoid arthritis.

Polyclonal Immunoglobulin (Ig) G from patients with rheumatoid arthritis (RA) and healthy subjects hydrolyzed carbobenzoxy-Val-Gly-Arg p-nitroanilide and D-Pro-Phe-Arg p-nitroanilide. RA IgG exhibited higher activity against the former substrate, but not the latter. On the other hand, RA IgG showed reduced activity against D-Pro-Phe-Arg methylcoumarinamide, when compared with those of the healthy controls. These results suggest that RA IgGs differ from normal IgGs in the substrate specificity of amidase activity. Preliminary studies have shown that two out of three RA IgG samples cleaved a pentapeptide--Gln-Arg-Arg-Ala-Ala--which is assumed to be associated with the risk of developing RA (Gregersen, P. K. et al. (1987), Arthritis Rheum. 30, 1205-1213). By contrast, virtually no cleavage of the same peptide was observed with IgG from healthy controls. A peptide analog, Gln-Arg-Arg-Trp-Ala, was not cleaved at all by any IgGs examined either from RA patients or healthy controls.

Amidohydrolases↗
PubMedDate not supplied

Two forms of basic trypsin-like arginine amidases in boar sperm.

Acrosin and newly detected basic arginine amidase were separated from boar sperm by affinity adsorption using lima bean trypsin inhibitor (LBTI) and aprotinin columns, respectively. These enzymes differed in various respects, including response against calcium chloride, amidolytic substrate specificity, and reaction against the inhibitor. They also differed widely in the affinity to LBTI. The difference appears to be expressed as the difference in ability of affinity of the enzymes with LBTI, thus leading to their separation.

Acrosin↗
PubMed1975

N-acetylmuramyl-L-alanine amidase of Vi phage III.

1. A lytic enzyme was isolated from Vi phage III-induced lysate of Salmonella typhi, and purified about 200-fold by chromatography on IRC-50, CM-cellulose, and Sephadex G-75 columns. 2. Both E. coli B murein and muropeptide C6 were digested on incubation with the lytic enzyme. The main product of murein and muropeptide C6 digestion is identical with tetrapeptide Ala-Glu-DAP-Ala. The release of amino groups during digestion was not accompanied by the appearance of either reducing groups or hexosamines. 3. It is concluded that Vi phage III-induced lytic enzyme is N-acetylmuramyl-L-alanine amidase, which cleaves the amide bond between N-acetylmuramic acid and L-alanine.

Amidohydrolases↗
PubMed1979

[Spectrum of amidase activity in a mutant of Brevibacterium].

Brevibacterium R 312 has a fairly non-specific amidase. Following the loss of this enzyme by mutation, the following enzymatic activities could be demonstrated: hydrolysis of urea, formamide, nicotinamide, L-glutamine, glycinamide and L-alpha-amino amids.

Amidohydrolases↗
PubMed1991

Influence of water miscible organic solvents on orange flavedo peptide amidase.

Due to the broad substrate spectrum and stability in some water-miscible organic solvents, the peptide amidase from orange flavedo was found to be a suitable enzyme for experiments in water-miscible organic solvents. Immobilization and the kind of organic solvent had no significant influence on the kinetic data while the polarity of the substrate caused a great difference in the apparent Km values. The results are explained by inadequate partition of the substrate between the microenvironment of the enzyme and the reaction solution.

Amidohydrolases↗
PubMedDate not supplied

A modified and improved assay for sperm amidase activity.

An assay for sperm amidase activity has been modified so that many samples can be measured rapidly, making it more suitable for use in a clinical setting. The modified assay gave the same results (P greater than 0.05) as its lengthier parent assay (Kennedy et al, 1989). The measured enzyme activity was proportional to the number of sperm assayed over the range tested (3.5 x 10(5) to 2.1 x 10(6) sperm). The within-assay coefficient of variation was 7.8 +/- 1.8% (average +/- SE, n = 12), and the between-assay coefficient of variation was 7.2 +/- 1.2% (n = 3). The sensitivity was 7.6 microIU/well.

Acrosin↗
PubMed1982

The significance of measurements of lipid peroxide and a newly-discovered amidase in inflammation.

Inflammation is a biological defence mechanism against noxious stimuli. Over-strong and oversuppressed inflammatory responses both lead to tissue damage and delay of tissue repair. Determination of inflammatory responses on the basis of chemical mediators, however, only informs about the degree of these responses themselves. It cannot show whether these responses are over-strong or oversuppressed. We have developed a prototype standard for safe judgement of the appropriateness of inflammatory responses: measurements of lipid peroxide (a product of tissue damage) and a newly-discovered amidase (related to wound healing).

Amidohydrolases↗
PubMed1975

Interaction of N-acetylmuramic acid L-alanine amidase with cell wall polymers.

In a previous communication (J. Biol. Chem. (1975) 250, 1676-1682), methods were described for the purification of the N-acetylmuramic acid L-alanine amidase from Bacillus subtilis ATCC 6051 and of a modifier protein which combines stoichiometrically with the enzyme and stimulates the activity approximately 3-fold. A detailed examination of the wall cleavage products obtained in the absence and in the presence of modifier indicates that the major effect of the modifier is not to change the enzyme velocity, but rather to change the pattern of cleavage from a more random pattern, when enzyme alone hydrolyzes the cell wall, to a sequential pattern in the presence of modifier protein. Tight binding of the enzyme to the cell wall and functional interaction with the modifier occur only when cell walls from Bacillus subtilis ATCC 6051 containing or teichoic acid are used as a substrate. We suggest that a general function of cell wall teichoic acids is to act as specific "allosteric" ligands for bacterial cell wall lytic enzymes as has been demonstrated previously in Pneumococci (Tomasz, A., and Westphal, M (1971) Proc. Natl. Acad. Sci. U.S.A. 68, 2627-2630).

Amidohydrolases↗
PubMedDate not supplied

Effects of substrate and separation method on acrosin amidase measurements.

The purpose of this study was to increase the accuracy and reproducibility of the acrosin amidase assay and to assess the effects of different methods of sperm isolation on total sperm acrosin activity. Specific acrosin activity was measured by the procedure described by Kennedy et al (1989) comparing the usual substrate, N-alpha-benzoyl-DL-arginine-p-nitroanalide hydrochloride (DL-BAPNA) with the L-(L-BAPNA) and D-(D-BAPNA) isomers. Activity measurements were also compared on sperm isolated by methods: (1) centrifugation through buffered Ficoll, (2) method 1 plus an additional wash in buffered Ficoll, (3) back addition of supernatant from method 1 to spermatozoa isolated by method 2, and (4) swim-up into synthetic human tubal fluid media (mHTF) and using L-BAPNA. The specific activity of acrosin was dependent on substrate concentration up to 2.1 mM DL-BAPNA and 2 mM L-BAPNA. The maximum reliable solubility of DL-BAPNA was approximately 2.1 mM in 10% dimethylsulfoxide (DMSO):90% detergent buffer. There were no solubility constraints for L-BAPNA through 6.3 mM (> 5 times Km). D-BAPNA (1 mM) was not hydrolyzed by acrosin. Mean specific acrosin activity was higher using 6.3 mM L-BAPNA (159 +/- 11.4 microIU/10(6) sperm) than with 2.1 mM DL-BAPNA (81.4 +/- 10.9 microIU/10(6) sperm; P < 0.001, n = 16). Sperm isolated by methods 2 and 4 had higher specific acrosin activity than sperm isolated by method 1 (P = 0.002). Sperm treated per method 3 had similar acrosin activity as sperm isolated by method 1 (140 +/- 14.1 vs. 149 +/- 13.8 microIU/10(6) sperm). The K(m) for acrosin, calculated through 6.3 mM L-BAPNA, was 0.6 microIU/10(6) sperm. L-BAPNA is superior to DL-BAPNA as substrate for a clinical acrosin assay, increasing the reproducibility and accuracy of the assay. Simple Ficoll separation is not completely effective at removing acrosin inhibitors and additional separation steps may be necessary to assess true acrosin activity.

Acrosin↗
PubMed1996

Transcription antitermination regulation of the Pseudomonas aeruginosa amidase operon.

In vivo titration experiments have demonstrated a direct interaction between the Pseudomonas aeruginosa transcription antiterminator, AmiR, and the mRNA leader sequence of the amidase operon. A region of 39 nucleotides has been identified which is sufficient to partially titrate out the AmiR available for antitermination. Site-directed mutagenesis has shown that the leader open reading frame has no role in the antitermination reaction, and has identified two critical elements at the 5' and 3' ends of the proposed AmiR binding site which are independently essential for antitermination. A T7 promoter/RNA polymerase-driven system shows AmiR-mediated antitermination, demonstrating a lack of promoter/polymerase specificity. Using the operon negative regulator, AmiC, immobilized on a solid support and gel filtration chromatography, an AmiC-AmiR complex has been identified and isolated. Complex stability and molecular weight assayed by gel filtration alter depending on the type of amide bound to AmiC. AmiC-AmiR-anti-inducer is a stable dimer-dimer complex and the addition of the inducer, acetamide, causes a conformational change which alters the complex stability and either this new configuration or dissociated AmiR interacts with the leader mRNA to cause antitermination.

Amidohydrolases↗
PubMed1976

[Benzoylarginine amidase activity of blood serum and plasma in acute pancreatitis].

In 40 patients with acute pancreatitis, examined 3-2 and 18-24 hours following the onset of the disease, benzoylarginine-amidase activity in blood serum and plasma was determined, as well as the activity of lipase and amylase in blood serum. A correlative dependence was found between the activity of amylase and lipase in blood serum, the activity of amylase in blood serum and trypsin-like activity in blood plasma of patients investigated in different time.

Acute Disease↗
PubMed1989

Peptide: N-glycosidase F: studies on the glycoprotein aminoglycan amidase from Flavobacterium meningosepticum.

Peptide: N-glycosidase from Flavobacterium meningosepticum was isolated in a homogeneous state and its physico-chemical characterization was accomplished. The reliability of the previously recorded assay procedures was assessed. Using an octaglycopeptide derived from ovomucoid a rapid and sensitive FPLC method was developed for the assay of enzymatic activity. Peptide: N-glycosidase was found to effect deglycosylation of glycoproteins bearing complex and/or multiantennary glycans even in their native state. In contrast, glycoproteins with high mannose and/or hybrid carbohydrates required denaturation to become susceptible to deglycosylation by the enzyme.

Amidohydrolases↗
PubMed1992

Characterization of the Bacillus subtilis CwbA protein which stimulates cell wall lytic amidases.

The Bacillus subtilis cell wall binding protein, CwbA, stimulated the cell wall lytic activities of the B. subtilis and B. licheniformis autolysins (CwlA and CwlM, respectively) in addition to that of the major B. subtilis autolysin (CwlB). Even though the substrate for the enzyme reaction was changed from B. subtilis cell wall containing a teichoic acid to Micrococcus luteus cell wall containing a teichuronic acid, the stimulatory effect of CwbA on CwlA activity was observed.

Bacillus subtilis↗