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Finn Wold – One of the best experts on this subject based on the ideXlab platform.

  • specificity determinants of acylaminoacyl peptide hydrolase
    Protein Science, 1992
    Co-Authors: Radha G. Krishna, Finn Wold

    Abstract:

    In an attempt to explore how specific features of the substrate’s primary structure may affect the activity of rabbit muscle acylaminoacyl-peptide hydrolase (EC 3.4.19.1), a number of acetylated peptides containing specific amino acid replacements in specific positions were prepared and compared as substrates for the hydrolase. The principal variants were D-Ala, Pro, and positive charges (His, Arg, Lys); in addition, the effect of the length of the peptide was also investigated in a less systematic manner. The substrates were either prepared by direct acetylation of peptides, by extension of the N-terminus with acetylamino acids or acetylpeptides, activated as N-hydroxysuccinimide esters, or by isolation of the N-terminal peptides from naturally occurring acetylated proteins. It was found that D-Ala on either side of the bond to be cleaved (positions 1 and 2) completely inhibited the enzymatic activity, whereas acetylated peptides with D-Ala in positions 3 or 4 were as good substrates as those containing L-Ala. Peptides with Pro in positions 2 were also inactive, and most of the peptides with Pro in the third position were very poor substrates; only the peptide Ac-AAP gave reasonably high activity (30% of Ac-AAA), which was reduced to 1-2% if additional residues were present at the C-terminus (Ac-AAPA, Ac-AAPAA). The presence of a positive charge in positions 2, 3, 4, 5, and 6 gave strong reduction in hydrolase activity varying with the charge’s distance from the N-terminus from 0 to 15-20% of the rates obtained with the reference peptides without positive charges.(ABSTRACT TRUNCATED AT 250 WORDS)

  • Specificity determinants of acylaminoacyl‐peptide hydrolase
    Protein Science, 1992
    Co-Authors: Radha G. Krishna, Finn Wold

    Abstract:

    In an attempt to explore how specific features of the substrate’s primary structure may affect the activity of rabbit muscle acylaminoacyl-peptide hydrolase (EC 3.4.19.1), a number of acetylated peptides containing specific amino acid replacements in specific positions were prepared and compared as substrates for the hydrolase. The principal variants were D-Ala, Pro, and positive charges (His, Arg, Lys); in addition, the effect of the length of the peptide was also investigated in a less systematic manner. The substrates were either prepared by direct acetylation of peptides, by extension of the N-terminus with acetylamino acids or acetylpeptides, activated as N-hydroxysuccinimide esters, or by isolation of the N-terminal peptides from naturally occurring acetylated proteins. It was found that D-Ala on either side of the bond to be cleaved (positions 1 and 2) completely inhibited the enzymatic activity, whereas acetylated peptides with D-Ala in positions 3 or 4 were as good substrates as those containing L-Ala. Peptides with Pro in positions 2 were also inactive, and most of the peptides with Pro in the third position were very poor substrates; only the peptide Ac-AAP gave reasonably high activity (30% of Ac-AAA), which was reduced to 1-2% if additional residues were present at the C-terminus (Ac-AAPA, Ac-AAPAA). The presence of a positive charge in positions 2, 3, 4, 5, and 6 gave strong reduction in hydrolase activity varying with the charge’s distance from the N-terminus from 0 to 15-20% of the rates obtained with the reference peptides without positive charges.(ABSTRACT TRUNCATED AT 250 WORDS)

Radha G. Krishna – One of the best experts on this subject based on the ideXlab platform.

  • specificity determinants of acylaminoacyl peptide hydrolase
    Protein Science, 1992
    Co-Authors: Radha G. Krishna, Finn Wold

    Abstract:

    In an attempt to explore how specific features of the substrate’s primary structure may affect the activity of rabbit muscle acylaminoacyl-peptide hydrolase (EC 3.4.19.1), a number of acetylated peptides containing specific amino acid replacements in specific positions were prepared and compared as substrates for the hydrolase. The principal variants were D-Ala, Pro, and positive charges (His, Arg, Lys); in addition, the effect of the length of the peptide was also investigated in a less systematic manner. The substrates were either prepared by direct acetylation of peptides, by extension of the N-terminus with acetylamino acids or acetylpeptides, activated as N-hydroxysuccinimide esters, or by isolation of the N-terminal peptides from naturally occurring acetylated proteins. It was found that D-Ala on either side of the bond to be cleaved (positions 1 and 2) completely inhibited the enzymatic activity, whereas acetylated peptides with D-Ala in positions 3 or 4 were as good substrates as those containing L-Ala. Peptides with Pro in positions 2 were also inactive, and most of the peptides with Pro in the third position were very poor substrates; only the peptide Ac-AAP gave reasonably high activity (30% of Ac-AAA), which was reduced to 1-2% if additional residues were present at the C-terminus (Ac-AAPA, Ac-AAPAA). The presence of a positive charge in positions 2, 3, 4, 5, and 6 gave strong reduction in hydrolase activity varying with the charge’s distance from the N-terminus from 0 to 15-20% of the rates obtained with the reference peptides without positive charges.(ABSTRACT TRUNCATED AT 250 WORDS)

  • Specificity determinants of acylaminoacyl‐peptide hydrolase
    Protein Science, 1992
    Co-Authors: Radha G. Krishna, Finn Wold

    Abstract:

    In an attempt to explore how specific features of the substrate’s primary structure may affect the activity of rabbit muscle acylaminoacyl-peptide hydrolase (EC 3.4.19.1), a number of acetylated peptides containing specific amino acid replacements in specific positions were prepared and compared as substrates for the hydrolase. The principal variants were D-Ala, Pro, and positive charges (His, Arg, Lys); in addition, the effect of the length of the peptide was also investigated in a less systematic manner. The substrates were either prepared by direct acetylation of peptides, by extension of the N-terminus with acetylamino acids or acetylpeptides, activated as N-hydroxysuccinimide esters, or by isolation of the N-terminal peptides from naturally occurring acetylated proteins. It was found that D-Ala on either side of the bond to be cleaved (positions 1 and 2) completely inhibited the enzymatic activity, whereas acetylated peptides with D-Ala in positions 3 or 4 were as good substrates as those containing L-Ala. Peptides with Pro in positions 2 were also inactive, and most of the peptides with Pro in the third position were very poor substrates; only the peptide Ac-AAP gave reasonably high activity (30% of Ac-AAA), which was reduced to 1-2% if additional residues were present at the C-terminus (Ac-AAPA, Ac-AAPAA). The presence of a positive charge in positions 2, 3, 4, 5, and 6 gave strong reduction in hydrolase activity varying with the charge’s distance from the N-terminus from 0 to 15-20% of the rates obtained with the reference peptides without positive charges.(ABSTRACT TRUNCATED AT 250 WORDS)

Akio Nakajima – One of the best experts on this subject based on the ideXlab platform.

  • Conformational analysis of periodic polypeptides
    Polymer Bulletin, 1993
    Co-Authors: Masahito Oka, Akio Nakajima

    Abstract:

    Theoretical conformational analysis was carried out for a periodic polypeptide composed of the repetitive Ala-Pro sequence, i.e., poly(Ala-Pro) using ECEPP and the conformational minimization procedure. Calculated results showed that a γ-helix is the most stable helical conformation of poly(Ala-Pro), and also that most of the stable helical conformations are other types γ-helices and β-helices with large value of the rise per residue. Obtained conformational preference of poly(Ala-Pro) indicates that the repetitive Ala-Pro sequence is a suitable amino-acid sequence for designing the rod-like backbone conformations of artificial proteins.

  • Theoretical conformational analysis on elastin analogue tetrapeptide Ac-Ala-Pro-Gly-Gly-NHMe
    Polymer Bulletin, 1991
    Co-Authors: Masahlto Oka, Yoshihiro Baba, Akihiro Kagemoto, Akio Nakajima

    Abstract:

    To investigate the role of the Val residue on stabilizing the γ-helix which is a proposed model conformation of elastin, conformational energy calculations using ECEPP were carried out for Ac-Ala-Pro-Gly-Gly-NHMe which is an analogous tetrapeptide for the sequence Val-Pro-Gly-Gly of elastin. The lowest-energy conformation is changed by the amino-acid substitution from Val to Ala residues, however, overall conformational characters in the ensemble of energy-minima of tetrapeptides are fundamentally maintained. The double-bend structure at Pro-Gly-Gly portion of Ac-Ala-Pro-Gly-Gly-NHMe is as favorable as that of Ac-Val-Pro-Gly-Gly-NHMe.