The preparation of chloromethylketone analogues of amino acids: Inhibition of leucine aminopeptidase

Birch, Patrick; El-Obeid, Humeida A.; Akhtar, Muhammad

doi:10.1016/0003-9861(72)90163-4

Cited by 47 publications

(16 citation statements)

References 5 publications

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“…The action of PheCH,Cl as a substrate-like compound is reversible in the initial phase. Similar results were obtained by Birch et al [8] describing the inhibiting effect of DL-LeuCH,cI. Further competitive inhibitors of leucine aminopeptidase have been reported by Jost [9,10] and Lasch et al [6].…”

supporting

confidence: 80%

Bovine-Lens Leucine Aminopeptidase. Kinetic Studies with Substrates and Substrate-Like Inhibitors

et al. 1974

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The inhibition of leucine aminopeptidase isolated from bovine eye lens by the chloromethyl ketones of L-phenylalanine (PheCH,Cl) and of L-leucine (LeuCH,Cl) has been studied. The inhibition by these substances is rather strong. Their action has been shown to be reversible and competitive with an inhibition constant of the order of Ki 0.1. mM. N-Methylated inhibitors and substrates have a lower affinity, N-acylated derivatives and normal ketones do not act as inhibitors.The inhibition constant of the tripeptide Thr(0But)-Phe-Pro with leucine hydrazide as substrate, Ki = 0.02 mM, agrees with other values which have been obtained using leucine 4-nitroanilide as substrate.A model for the binding step in the active center of the leucine aminopeptidase has been developed from the Ki values and the calculated free energy of binding AGO of the chloromethyl ketones and methyl ketones with a free or N-methylated a-amino group and the Km of their analogous amino acid hydrazides. These model is as follows.1. The hydrophobic residues of amino-acid hydrazides and amides causes a hydrophobic "one-site" bonding with the enzyme. As in the case of chloromethyl ketones, methyl ketones and peptides the affinity increaseswith an additional C-terminal hydrophobic part. It results in a hydrophobic "three-site" bonding of the inhibitors and peptide substrates. 3. The complexation of the substrate or inhibitor is a preliminary condition towards the hydrophobic binding. Therefore a sterically attainable basic &-amino function in the unprotonated form is necessary.The model is discussed and compared with other kinetic data in the literature.Besides chemical and optical methods, the comparison of kinetic parameters of differently modified substrates and competitive inhibitors enables one to obtain further information about the mechanism of binding in the active center of an enzyme. From this point of view the binding constants l / K m and I/Ki respectively and the corresponding free energy of binding are of particular interest.

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confidence: 80%

Bovine-Lens Leucine Aminopeptidase. Kinetic Studies with Substrates and Substrate-Like Inhibitors

et al. 1974

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“…The conversion of a carboxyl group into a Vol. 137 diazomethyl ketone by activation as the mixed anhydride (Birch et al, 1972) indicated a promising alternative route for lysine chloromethyl ketones.…”

Section: Results and Discussion Synthesis Ofinhibitorsmentioning

confidence: 99%

Affinity labelling of proteinases with tryptic specificity by peptides with C-terminal lysine chloromethyl ketone

Coggins

Kray

Shaw

1974

Biochemical Journal

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Methods are described for the synthesis of peptides terminating in Lys-CH(2)Cl. The products were examined as affinity labels for several enzymes of trypsin-like specificity which are resistant to Tos-Lys-CH(2)Cl. In part, the inertness of the latter may be due to the sulphonamide group, since Z-Lys-CH(2)Cl was more effective. However, a number of tripeptides with C-terminal Lys-CH(2)Cl were superior in their ability to inactivate subtilisin, thrombin and plasma kallikrein. The possibility of developing enzyme-specific reagents selective for members within the trypsin-like group is demonstrated by Ala-Phe-Lys-CH(2)Cl, which readily inactivates plasma kallikrein but not thrombin.

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“…Several transition state analog inhibitors have been synthesized which resemble the gem-diol intermediate after attack of a water nucleophile on the peptide bond. These include aminophosphonates [20,21], aminoaldehydes [22], chloromethanes [23], and peptides containing a ketomethylene amide bond replacement [24]. Also, amino acid hydroxamates [25] and L-leucylthiol [26] are strong inhibitors of LAP.…”

Section: Activity and Specificitymentioning

confidence: 99%

Leucyl Aminopeptidase (Animal)

Sträter¹,

Lipscomb²

2013

Handbook of Proteolytic Enzymes

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The preparation of chloromethylketone analogues of amino acids: Inhibition of leucine aminopeptidase

Cited by 47 publications

References 5 publications

Bovine-Lens Leucine Aminopeptidase. Kinetic Studies with Substrates and Substrate-Like Inhibitors

Bovine-Lens Leucine Aminopeptidase. Kinetic Studies with Substrates and Substrate-Like Inhibitors

Affinity labelling of proteinases with tryptic specificity by peptides with C-terminal lysine chloromethyl ketone

Leucyl Aminopeptidase (Animal)

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