The Specificity of Penicillopepsin

1971 ◽  
Vol 49 (10) ◽  
pp. 1134-1149 ◽  
Author(s):  
G. Mains ◽  
Miho Takahashi ◽  
J. Šodek ◽  
T. Hofmann
Keyword(s):  
Amino Acid ◽  
Glutamic Acid ◽  
Ph Dependence ◽  
Random Copolymer ◽  
The Other ◽  
High Rate ◽  
Hydrophobic Amino Acid ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Very High

The specificity of penicillopepsin was investigated with a number of different substrates. In agreement with earlier work (1), no action was observed on di- and tripeptide and ester substrates. However, the pepsin substrate carbobenzoxyglycylglycylphenylalanylphenylalanine 3-(4-pyridyl)propyl-1 ester was hydrolyzed between the two phenylalanine residues. No cleavage of homopolymers of glycine, alanine, and glutamic acid and the random copolymer of glutamic acid and tyrosine was observed. Polymers of lysine, lysine and tyrosine (2:1), and lysine, glutamic acid, and tyrosine (13:20:1) were, however, hydrolyzed giving mainly tripeptides to pentapeptides. Polylysine hydrolysis showed a pH dependence centering about a group of pK between 3 and 4. In glucagon and the S-sulfo B-chain of insulin, penicillopepsin hydrolyzed the same peptide bonds as the other acidic proteases, including pepsin and rennin, with very few exceptions. There are, however, distinct differences between the action of penicillopepsin and that of other proteases of low specificity. Peptide bonds which have a hydrophobic amino acid in the P1′ position (as defined by Berger and Schechter, Ref. 2) are preferentially cleaved by penicillopepsin. A kinetic study of the hydrolysis of bovine serum albumin showed very high rate constants for the initial cleavages. The present study shows the requirement for an extended binding site in penicillopepsin.

Covalently Bound Flavin in D-6-Hydroxynicotine Oxidase from Arthrobacter oxidans

1972 ◽  
Vol 27 (9) ◽  
pp. 1073-1074 ◽  
Author(s):  
M. Brühmüller ◽  
H. Möhler ◽  
K. Decker
Keyword(s):  
Amino Acid ◽  
Flavin Adenine Dinucleotide ◽  
Ph Dependence ◽  
Spectral Characteristics ◽  
Amino Acid Derivative ◽  
Aminopeptidase M ◽  
Arthrobacter Oxidans ◽  
Layer Chromatography ◽  
Hydrolysis Of ◽  
Covalently Bound

D-6-hydroxynicotine oxidase contains 1 mole of FAD covalently bound to one mole of enzyme. To identify the covalent linkage between FAD and protein, an amino acid derivative of riboflavin (HNO-flavin) was isolated and purified. It was obtained from flavin peptides by hydrolysis with 6 N HCl at 95°C or with aminopeptidase M. The riboflavin derivative had the spectral characteristics of 8α-substituted flavins. It showed a pH-dependence of fluorescence with a pK of 4.65 and 86% quenching at pH 7. In thin layer chromatography it was identical with 8α-(N-3-histidyl)-riboflavin. Hydrolysis of HNO-flavin in 6 N HCl at 125°C liberated 1 mole of histidine per mole of flavin as shown by amino acid analysis. Since FAD is the coenzyme of D-6-hydroxynicotine oxidase, these results are taken as evidence that this enzyme contains 8a- (N-3-histidyl) -flavin-adenine-dinucleotide in the active center.

scholarly journals Cathepsin B, the lysosomal thiol proteinase of calf liver

1969 ◽  
Vol 114 (4) ◽  
pp. 673-678 ◽  
Author(s):  
O. Snellman
Keyword(s):  
Cathepsin B ◽  
Ph Dependence ◽  
Gel Filtration ◽  
Chelating Agent ◽  
Thiol Group ◽  
Maximum Activity ◽  
Active Centre ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Thiol Proteinase

Cathepsin B from calf liver was obtained by a method involving preparation of a lysosomal–mitochondrial pellet and treatment of this pellet with acetone. The material was extracted with an acid buffer, pH4·0, and then precipitated from the extract with acetone. The precipitate was dissolved in phosphate buffer, pH7·4, and subjected to gel filtration on Sephadex G-200 and G-100. The cathepsin B emerged in a range of molecular weight much lower than 50000 as a well-defined component. The purity of this material was checked by electrophoresis. To obtain maximum activity the enzyme had to be activated with a chelating agent and a reducing agent (i.e. EDTA and cysteine). A number of different substrates were used. The enzyme was active for the hydrolysis of both peptide bonds and ester bonds and had approximately equal reactivity in the two cases. The pH-dependence of the hydrolysis was the same with both substrates. The binding of the substrates was half-maximal at pH4·5 and at pH6·8. A thiol group occurred in the active centre but this group ought to have a much higher pK than that found in this enzyme.

Enantioselective hydrolysis of hydrophobic amino acid derivatives by lipases

1992 ◽  
Vol 14 (6) ◽  
pp. 461-464 ◽  
Author(s):  
Aih-Jing Chiou ◽  
Shih-Hsiung Wu ◽  
Kung-Tsung Wang
Keyword(s):  
Amino Acid ◽  
Amino Acid Derivatives ◽  
Enantioselective Hydrolysis ◽  
Hydrophobic Amino Acid ◽  
Hydrolysis Of

First Metatarsalphalangeal Joint Arthrodesis: Evaluation of Plate and Screw Fixation

2009 ◽  
Vol 30 (8) ◽  
pp. 752-757 ◽  
Author(s):  
Gordon L. Bennett ◽  
James Sabetta
Keyword(s):  
Screw Fixation ◽  
Ease Of Use ◽  
The Other ◽  
High Rate ◽  
Fusion System ◽  
Hardware Failure ◽  
Low Profile ◽  
Final Followup ◽  
Implant System ◽  
Very High

Background: First metatarsalphalangeal joint (MTPJ) arthrodesis is a commonly performed procedure for the treatment of a variety of conditions affecting the hallux. There are several different methods to accomplish the fusion. We utilized a method incorporating a ball and cup preparation of the joint, followed by stabilization of the arthrodesis site utilizing the Accutrak congruent first MTPJ fusion set. Materials and Methods: We prospectively evaluated two hundred consecutive patients who underwent first MTPJ arthrodeses utilizing the Accutrak congruent first MTPJ fusion set. Patients were evaluated preoperatively, postoperatively, and at a final followup, utilizing the AOFAS forefoot scoring system. Results: Two hundred consecutive patients underwent first MTPJ arthrodeses by the same surgeon. All but three feet (230/233) (98.7%) went on to solidly fuse. Three of the patients did not fuse solidly. One patient broke two of the screws, and the other two patients did not have hardware failure. All patients dramatically improved their AOFAS scores compared with pre-surgical values. There were three minor hardware problems in the group of patients who solidly fused their joint. Conclusion: We concluded that a solid first MTPJ fusion results in excellent function and pain relief. The Accutrak first MTPJ fusion system would appear to be an ideal implant system to accomplish a fusion because of its low profile, strength, and ease of use. Compared to other methods we have used, this procedure results in a very high rate of fusion, with minimal complications and excellent patient satisfaction.

scholarly journals Availability to pigs of amino acids in cereal grains

1981 ◽  
Vol 46 (1) ◽  
pp. 159-171 ◽  
Author(s):  
M. R. Taverner ◽  
I. D. Hume ◽  
D. J. Farrell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
The Other ◽  
Cereal Grains ◽  
Sorghum Vulgare ◽  
Amino Acid Availability

1. Pigs prepared with re-entrant ileal cannulas were used to determine the ileal availability of amino acids in nine cereal grains including five wheats, sorghum (Sorghum vulgare Pers.), maize, barley and Triticale.2. The average true availability of amino acids in these grains was 0·88 but there were consistent differences in availability among amino acids. Generally, lysine and threonine were among the least available amino acids while glutamic acid and arginine were among the most available amino acids in cereal protein.3. There was as much variation in amino acid availability within a grain species (wheat) as among the other grains.

scholarly journals The sites of hydrolysis of dipeptides containing leucine and glycine by rat jejunum in vitro

1969 ◽  
Vol 114 (4) ◽  
pp. 855-861 ◽  
Author(s):  
E. B. Fern ◽  
R. C. Hider ◽  
D. R. London
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
The Other ◽  
Peptidase Activity ◽  
Rat Jejunum ◽  
Effective Inhibitor ◽  
Inhibitory Effects ◽  
Molar Basis ◽  
Hydrolysis Of

1. The effect of peptides containing leucine and glycine on accumulation of leucine and glycine by everted jejunal rings was studied. 2. It was shown that, on a molar basis, leucyl-leucine is a more effective inhibitor of uptake of [14C]leucine than is either leucylglycine or glycyl-leucine. These latter dipeptides behave alike. 3. The concentration of the dipeptides and their constituent amino acids in both the incubation medium and the tissue has been followed in these experiments by amino acid analysis. No leucine-containing peptides were observed in the tissue. 4. The inhibitory effects of the mixed dipeptides are altered by pH changes in an analogous way to the alterations in peptidase activity. 5. The experimental results indicate that leucine-containing peptides are hydrolysed before the transport step. 6. Glycylglycine, on the other hand, has only a small effect on the accumulation of glycine, although large amounts of the peptide accumulate unchanged in the tissue. This suggests that glycylglycine is taken up by a different mechanism to that for the leucine dipeptides.

Endogenous amino acid flows at the terminal ileum of broilers, layers and adult roosters

2004 ◽  
Vol 79 (2) ◽  
pp. 265-271 ◽  
Author(s):  
V. Ravindran ◽  
W. H. Hendriks
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Terminal Ileum ◽  
Crude Protein ◽  
Amino Acid Profile ◽  
The Other ◽  
Endogenous Protein ◽  
Abundant Amino Acid ◽  
Endogenous Amino Acid

AbstractEndogenous flows of nitrogen and amino acids at the terminal ileum of broilers (6 weeks old), layers (70 weeks old) and adult roosters (70 weeks old) were determined using the peptide alimentation method. The ileal endogenous output of nitrogen and total amino acids in broilers, layers and roosters, expressed as mg/kg dry matter intake, were similar (F > 0-05). Endogenous flows were similar (F > 0-05) for nine of the 17 amino acids analysed, but the flows of serine, glutamic acid, proline, alanine, isoleucine, tyrosine, arginine and methionine differed (P < 0-05) among the classes of chickens. The amino acid profile of endogenous protein, expressed asg/100 g crude protein, did not differ (F > 0-05) between the three classes of chickens, except for serine, glutamic acid, proline and isoleucine. The concentrations of proline were higher (F < 0-05) in broilers, compared with the other two groups. The concentrations of glutamic acid in layers were lower (F < 0-05) than the other two groups. The concentrations of serine and isoleucine were higher (F < 0-05) in roosters than the other two groups. In all three groups, the most abundant amino acid in the ileal endogenous protein was glutamic acid, followed by aspartic acid, proline, serine, glycine and threonine. The present study provides estimates for endogenous amino acid flow at the terminal ileum in broilers, layers and adult roosters under normal physiological conditions.

STUDIES ON RDX AND RELATED COMPOUNDS: I. THE DIRECT NITROLYSIS OF HEXAMINE TO RDX

1950 ◽  
Vol 28b (11) ◽  
pp. 701-714 ◽  
Author(s):  
A. H. Vroom ◽  
C. A. Winkler
Keyword(s):  
Nitric Acid ◽  
Initial Rate ◽  
High Rate ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
Rate Controlling Step ◽  
Very High ◽  
Do So

Maximum yields, of about 40%, of RDX were obtained with nitric acid of all concentrations down to 88%, providing the molar ratio of nitric acid to hexamine was sufficiently high. The rate of nitrolysis increased rapidly as the molar ratio of nitric acid to hexamine was increased and continued to do so after the molar ratio was raised above that required for maximum yields. The initial rate was shown to have an upper limit, however, at very high molar ratios. An intermediate in the nitrolysis reaction was isolated and identified as 3,5-dinitrocyclotrimethylenetriamine-1-nitrate (I). (I) was formed rapidly in sufficient quantities of 85 to 91% nitric acid at 0 °C., but had a high rate of decomposition which was independent of both acid concentration and ratio of nitric acid to (I) with 80 to 90% nitric acid. Under nitrolysis conditions some of the hexamine was converted to products not capable of giving RDX, owing apparently to hydrolysis of precursors to (I). The activation energy for the conversion of (I) to RDX was found to be identical with that for the rate controlling step of the conversion of hexamine to RDX. This fact, together with the general kinetic behavior of (I), provided evidence that (I) was a true intermediate and that its reaction to RDX was the rate controlling step in the direct nitrolysis of hexamine. The mechanism of the over-all reaction is discussed in relation to published information concerning the constitution of concentrated nitric acid. Nitracidium ion is believed to be the active nitrolyzing agent.

scholarly journals Lack of influence of low temperature, light and growth substances on phytochrome resynthesis in coleoptiles of irradiated oat seedlings

2014 ◽  
Vol 53 (2) ◽  
pp. 271-278
Author(s):  
Jan Kopcewicz ◽  
Mariusz Cymerski ◽  
Kazimierz Madela
Keyword(s):  
Low Temperature ◽  
Large Fraction ◽  
Elongation Growth ◽  
The Other ◽  
High Rate ◽  
Growth Substances ◽  
Etiolated Seedlings ◽  
High Level ◽  
Very High

The photoconversion of phytochrome P<sub>R</sub> into the P<sub>FR</sub> form causes at the same time the destruction of the initial large fraction of phytochrome found in the coleoptiles of etiolated oat seedlings. Factors such as low temperature, light of different wavelengths or growth substances are not capable of preventing the progressive destruction and restore the synthesis of phytochrome. Thus an abnormally high level of phytochrome is found only in etiolated seedlings. Such seedlings, on the other hand, are characterized by a very high rate of elongation growth. The role of phytochrome in the control of deetiolation of seedlings is discussed.

AN ANTIVIRAL SUBSTANCE FROM PENICILLIUM CYANEO-FULVUM BIOURGE: III. STUDIES ON THE NATURE OF THE ANTIVIRAL SUBSTANCE

1967 ◽  
Vol 13 (11) ◽  
pp. 1481-1488
Author(s):  
Delfa Syeklocha ◽  
Patricia M. Cooke ◽  
J. W. Stevenson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Positive Charge ◽  
Reducing Sugar ◽  
The Other ◽  
Two Dimensional ◽  
Carbohydrate Complex ◽  
Amido Black ◽  
Antiviral Substance ◽  
Hydrolysis Of

An attempt has been made to determine the nature of an antiviral substance derived from Penicillium cyaneo-fulvum. Although the material was available only in semipurified state, horizontal electrophoresis showed just two components present, one with a positive charge and the other with a negative one. Both stained with mucicarmine and Amido black. After hydrolysis of the preparation, 13 amino acids were identified by two-dimensional chromatography. Preliminary studies indicate that the semipurified material contains 21–25% reducing sugar. The effect of a variety of enzymes on the activity of the preparation has been studied. The results indicate that the antiviral substance may be an amino acid – carbohydrate complex.

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