Publications

• A broad diversity of volatile carboxylic acids, released by a bacterial aminoacylase from axilla secretions, as candidate molecules for the determination of human-body odor type.

  Natsch A., Derrer S., Flachsmann F., Schmid J.

  Human body odor is to a large part determined by secretions of glands in the axillary regions. Two key odoriferous principles, 3-methylhex-2-enoic acid (3MH2; 4/5) and 3-hydroxy-3-methylhexanoic acid (HMHA; 6) have been shown to be released from glutamine conjugates secreted in the axilla by a spe ... >> More

  Human body odor is to a large part determined by secretions of glands in the axillary regions. Two key odoriferous principles, 3-methylhex-2-enoic acid (3MH2; 4/5) and 3-hydroxy-3-methylhexanoic acid (HMHA; 6) have been shown to be released from glutamine conjugates secreted in the axilla by a specific N(alpha)-acyl-glutamine aminoacylase (N-AGA) obtained from axilla isolates of Corynebacteria sp. However, the low number of different odorants reported in humans stands in contrast to the observed high inter-individual variability in body odors. Axilla secretions of individual donors were, therefore, analyzed in detail. The secretions were treated with N-AGA, analyzed by GC/MS, and compared to undigested controls. Over 28 different carboxylic acids were released by this enzyme from odorless axilla secretions (Table 1). Many of these body odorants have not been reported before from a natural source, and they include several aliphatic 3-hydroxy acids with 4-Me branches, 3,4-unsaturated, 4-Et-branched aliphatic acids, and a variety of degradation products of amino acids. The odor threshold of some of the acids was found to be in the range of 1 ng. Most of these compounds were present in all donors tested, but in highly variable relative amounts, and they are, thus, candidate molecules as key components of a 'compound odor' determining the individual types of human body odor. << Less

  Chem. Biodivers. 3:1-20(2006) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• A specific bacterial aminoacylase cleaves odorant precursors secreted in the human axilla.

  Natsch A., Gfeller H., Gygax P., Schmid J., Acuna G.

  Human axillary odor is known to be formed upon the action of Corynebacteria sp. on odorless axilla secretions. The known axilla odor determinant 3-methyl-2-hexenoic acid was identified in hydrolyzed axilla secretions along with a chemically related compound, 3-hydroxy-3-methylhexanoic acid. The na ... >> More

  Human axillary odor is known to be formed upon the action of Corynebacteria sp. on odorless axilla secretions. The known axilla odor determinant 3-methyl-2-hexenoic acid was identified in hydrolyzed axilla secretions along with a chemically related compound, 3-hydroxy-3-methylhexanoic acid. The natural precursors of both these acids were purified from non-hydrolyzed axilla secretions. From liquid chromatography/mass spectrometry analysis, it appeared that the acids are covalently linked to a glutamine residue in fresh axilla secretions, and the corresponding conjugates were synthesized for confirmation. Bacterial isolates obtained from the human axilla and belonging to the Corynebacteria were found to release the acids from these odorless precursors in vitro. A Zn(2+)-dependent aminoacylase mediating this cleavage was purified from Corynebacterium striatum Ax20, and the corresponding gene agaA was cloned and heterologously expressed in Escherichia coli. The enzyme is highly specific for the glutamine residue but has a low specificity for the acyl part of the substrate. agaA is closely related to many genes coding for enzymes involved in the cleavage of N-terminal acyl and aryl substituents from amino acids. This is the first report of the structure elucidation of precursors for human body odorants and the isolation of the bacterial enzyme involved in their cleavage. << Less

  J. Biol. Chem. 278:5718-5727(2003) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Isolation of a bacterial enzyme releasing axillary malodor and its use as a screening target for novel deodorant formulations.

  Natsch A., Gfeller H., Gygax P., Schmid J.

  Axillary odor is known since 50 years to be formed upon the action of Corynebacteria on odorless axilla secretions, but the nature of the bacterial enzymes involved in this process remained a mystery. We identified the known axilla odor determinant 3-methyl-2-hexenoic acid in hydrolyzed axilla sec ... >> More

  Axillary odor is known since 50 years to be formed upon the action of Corynebacteria on odorless axilla secretions, but the nature of the bacterial enzymes involved in this process remained a mystery. We identified the known axilla odor determinant 3-methyl-2-hexenoic acid in hydrolyzed axilla secretions along with a new, chemically related compound, 3-hydroxy-3-methyl-hexanoic acid. The natural, odorless precursors of both these acids were purified from non-hydrolyzed fresh axilla secretions. The malodorous acids were shown to be covalently linked to a glutamine residue in fresh axilla secretions. Corynebacteria, but not Staphylococci, isolated from the axilla were found to release the acids from these precursors in vitro. A Zn(2+) -dependent aminoacylase mediating this cleavage was then purified from Corynebacterium striatum Ax20 and the corresponding gene agaA was cloned and heterologously expressed in Escherichia coli. Based on these biochemical findings, novel approaches in research on axilla malodor control are presented: (a) With a new test method using the isolated Corynebacteria and their enzymatic activity, the direct malodor-controlling activity of existing cosmetic ingredients was evaluated. (b) The structure of the natural malodor precursor was modified by replacing the malodor acid with fragrance molecules. These new fragrance precursors were shown to be cleaved by the same aminoacylase. << Less

  Int. J. Cosmet. Sci. 27:115-122(2005) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.