Search results for "inope"

Cell Surface-Bound Leucine Aminopeptidase: Target of the Immunomodulator Bestatin

1986

The study of low molecular weight enzyme inhibitors of microbial origin was initiated by Umezawa in 1965 (see Umezawa 1972). Since the discovery of an inhibitor of tyrosine hydroxylase, nearly 50 inhibitors of various enzymes have been found by him; their structures were elucidated and most of the compounds were chemically synthesized (Umezawa 1982). Among them one inhibitor of both aminopeptidase B and the ectoenzyme, leucine aminopeptidase was found in 1976 and was termed bestatin (Fig. 1), [(2S,3R)-3-amino-2-hydroxy 4-phenyl-butanoyl]-(S)-leucine (Umezawa et al. 1976).

Purification and characterization of leucine aminopeptidase from kidney bean cotyledons

1992

A leucine aminopeptidase (EC 3,4,11.1) was purified from cotyledons of resting kidney beans (Phaseolus vulgaris L. cv. Processor) by acidic extraction, ammonium sulfate fractionation and chromatography on DEAE-Sephacel, Sephacryl S-300, Mono Q HPLC and Superose HPLC columns. The yield of the 317-fold purified enzyme was 9%. On gel filtrations on Sephacryl S-300 and Superose HPLC the elution volumes of the enzyme corresponded to an M, of 360 000. The enzyme gave one band on native gel electrophoresis and an electrophoretic titration in an immobilized pH gradient gave a single curve with a pI of 4.8. Two bands were observed in an SDS-gel electrophoresis with Mr values of 58 000 and 60 000 bot…

Comperative studies with Culex pipiens egg rafts. Immunogenetic, electrophoretic and enzymatic analysis of unfertilized, compatible and incompatible …

1973

By applying immunologic, electrophoretic and enzymatic methods, extracts of different raft types of Culex pipiens were analysed. Rafts of the crosses Pa x Pa and Ha x Ha contained four common antigens, while unfertilized rafts of Pa and Ha (no antisera were prepared against them) and rafts of the crosses Og x Og, Og x Pa, and Pa x Og shared three common antigens with the remaining raft extracts. Disk-electrophoresis of raft extracts in acrylamide gel resulted in different electropherograms. Ten protein bands were common to all these raft types. The unfertilized rafts of Pa and Ha yielded three more protein bands, the crosses Pa x Ha and Ha x Pa one more, the crosses Og x Og and Pa x Og thre…

Activities of some peptidases and proteinases in germinating kidney bean, Phaseolus vulgaris

1986

The activities of aminopeptidase (EC 3.4.11), dipeptidase (EC 3.4.13), carboxypeptidase (EC 3.4.16), naphthylamidase (EC 3.4.11) and proteinases (EC 3.4.21) were assayed in extracts from the cotyledons and the axial tissues of resting and germinating kidney beans (Phaseolus vulgaris L. cv. Processor). The activities of the alkaline peptidases (aminopeptidase hydrolyzing Leu-Tyr at pH 9.2 and dipeptidase acting on Ala-Gly at pH 8.5) and naphthylamidases (hydrolyzing Leu-β-naphthylamide at pH 6.4) were high in the cotyledons of resting seeds, but decreased during germination. This decrease was faster than the loss of the total nitrogen. On the contrary, the activities of carboxypeptidase (hyd…

A three-component Mannich-type condensation leading to phosphinic dipeptides—extended transition state analogue inhibitors of aminopeptidases

2011

Abstract N-Protected α-aminoalkylphosphinic acids bearing a P–H function were found to be novel practical building blocks in three-component condensations with formaldehyde and secondary amines (amino acids). Such Mannich-type N -phosphonomethylation is a common approach for phosphorus acid derived substrates and leads to multifunctional (phosphonic/amino/carboxylic) compounds of diverse relevance. The utility of this reaction was examined for construction, in a single synthetic step, of advanced phosphinic pseudodipeptides designed to act as extended transition state analogue inhibitors of selected aminopeptidases. Phosphinomethylation of primary amino acids was less efficient and yielded …

The influence of α-aminophosphonic acids on the activity of aminopeptidase from barley seeds—an approach to determine the enzyme specificity

2015

Inhibitory potencies of 24 α-aminophosphonic acids against barley seeds (Hordeum vulgare L.) metallo-aminopeptidase have been determined to evaluate structural requirements of this enzyme. The enzyme was sensitive mostly to the influence of phosphonic acid analogues of phenylalanine and its homologues, thus showing narrow specificity if compared with porcine aminopeptidases M1 and M17 and with Plasmodium aminopeptidase M17.

Localization and Activity of Naphthylamidases in Germinating Seeds of Scots Pine, Pinus sylvestris

1976

Extracts prepared from endosperms of germinating seeds of Scots pine, Pinus sylvestris L., rapidly hydrolysed the β-naphthylamides of L-phenylalanine and L-leucine optimally at pH 6.5 and that of L-arginine at pH 7.7. Disc electrophoresis followed by activity staining showed that the activities were due to two naphthylamidases (aminopeptidases) with different substrate specificities. Seeds were allowed to germinate at 20°C on agar gel in the dark and the activities on the three substrates were assayed from separated endosperms and seedlings at various stages of germination. The activities in the endosperm of resting seeds were relatively high and they remained unchanged throughout the perio…

The Application of Salicylic Acid Amide for 4-Dimethylaminoaniline Determination

1993

KIELELLINEN ERITYISVAIKEUS – EI PELKÄSTÄÄN KIELELLISTEN TAITOJEN ONGELMA

2016

Kielellisen erityisvaikeuden ajatellaan olevan ensisijaisesti kielellisten taitojen ongelma. On kuitenkin todennäköistä, että kielelliseen erityisvaikeuteen liittyy myös ei-kielellisiä vaikeuksia. Tämän artikkelin tavoitteena on luoda katsaus eksekutiivisiin toimintoihin ja prosessointinopeuteen osana kielellistä erityisvaikeutta. Tutkimusten perusteella näyttää siltä, että kielelliseen erityisvaikeuteen liittyy kognitiiviseen joustavuuteen, inhibitioon, työmuistiin, tarkkaavuuteen sekä prosessointinopeuteen liittyviä vaikeuksia ainakin osalla kielihäiriöistä lapsista. Kielellisen erityisvaikeuden kliinisessä diagnostiikassa ja kuntoutuksessa on syytä huomioida myös ei-kielelliset vaikeudet…

Estudio de las bases de la resistencia a las proteínas insecticidas de bacillus thuringiensis en ostrinia nubilalis

2013

Ostrinia nubilalis (Hübner) es una de las plagas más devastadoras de los cultivos de maíz de Europa y Norte América, y a nivel económico la obtención de un control eficaz de esta plaga es un logro fundamental. En 1996, se permitió la comercialización de las plantas transgénicas que llevan insertado en el genoma un gen procedente de Bacillus thuringiensis (Berliner) (Bt) y que codifica para una proteína insecticida de las que esta bacteria produce en forma de cristales paraesporales (proteínas Cry). A partir de esta fecha, la adopción de los cultivos de maíz Bt que expresan en concreto la toxina Cry1Ab ha ido aumentando progresivamente en todo el mundo, con el resultado de que las pérdidas e…