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MAURICE WELSCH
Β. ANTIBIOTICS WHOLLY OR PARTIALLY DERIVABLE FROM AMINO ACIDS
A few antibiotics appear to be simple derivatives of single amino
acids, and others contain an amino acid or related compound as an important moiety. Another group of antibiotics comprises oligopeptides and
a larger group, polypeptides. Among the latter, some contain, in addition
to the peptide chain, other constituents of variable importance, such as a
heterocyclic chromophore group, as in the actinomycins, or hydroxy fatty
acids, as in the peptolides. Colicins are believed to be, at least in part, of
a protein nature (67); certain typical protein enzymes, able to kill sensitive species of microorganisms, are obviously to be included among antibiotics (68a). Some heterocyclic compounds with antibiotic properties,
or which are part of an antibiotic, appear to be biosynthesized from
aromatic amino acids or to stem from their metabolic pathway. Finally,
purine and pyrimidine moieties are also biochemically linked to amino
acid metabolism.
1. Single Amino Acids and Derivatives in Antibiotics
The presence of an amino acid or related moiety in some sugarcontaining antibiotics has already been mentioned. For instance, Omethyl-L-tyrosine is a part of puromycin (XIV) and «-methyl-D-serine
of amicetin A and bamicetin (XV).
Simple derivatives of amino acids, such as O-carbamylserine (XXXI),
have been isolated from streptomycete cultures (68b) and some of them
are endowed with antibiotic properties. Oxamycin or D-cycloserine
(XXXII), from S. orchidaceus, S. garyphalus, S. fovendulae, S. roseochromogenes, and S. nagasakiensis, formally resembles D-serine and is
possibly related biogenetically to alanine. It acts in a manner generally
similar to that of the penicillins by interfering with cell wall biosynthesis.
It appears to inhibit specifically the incorporation of D-alanyl residues
MAURICE WELSCH
Β. ANTIBIOTICS WHOLLY OR PARTIALLY DERIVABLE FROM AMINO ACIDS
A few antibiotics appear to be simple derivatives of single amino
acids, and others contain an amino acid or related compound as an important moiety. Another group of antibiotics comprises oligopeptides and
a larger group, polypeptides. Among the latter, some contain, in addition
to the peptide chain, other constituents of variable importance, such as a
heterocyclic chromophore group, as in the actinomycins, or hydroxy fatty
acids, as in the peptolides. Colicins are believed to be, at least in part, of
a protein nature (67); certain typical protein enzymes, able to kill sensitive species of microorganisms, are obviously to be included among antibiotics (68a). Some heterocyclic compounds with antibiotic properties,
or which are part of an antibiotic, appear to be biosynthesized from
aromatic amino acids or to stem from their metabolic pathway. Finally,
purine and pyrimidine moieties are also biochemically linked to amino
acid metabolism.
1. Single Amino Acids and Derivatives in Antibiotics
The presence of an amino acid or related moiety in some sugarcontaining antibiotics has already been mentioned. For instance, Omethyl-L-tyrosine is a part of puromycin (XIV) and «-methyl-D-serine
of amicetin A and bamicetin (XV).
Simple derivatives of amino acids, such as O-carbamylserine (XXXI),
have been isolated from streptomycete cultures (68b) and some of them
are endowed with antibiotic properties. Oxamycin or D-cycloserine
(XXXII), from S. orchidaceus, S. garyphalus, S. fovendulae, S. roseochromogenes, and S. nagasakiensis, formally resembles D-serine and is
possibly related biogenetically to alanine. It acts in a manner generally
similar to that of the penicillins by interfering with cell wall biosynthesis.
It appears to inhibit specifically the incorporation of D-alanyl residues