Urocanic acid isomers: relation to body site, pigmentation, stratum corneum thickness and photosensitivity

1997 ◽  
Vol 289 (9) ◽  
pp. 501-505 ◽  
Author(s):  
F. Fine Olivarius ◽  
H. C. Wulf ◽  
P. Therkildsen ◽  
T. Poulsen ◽  
J. Crosby ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Urocanic Acid ◽  
Body Site

scholarly journals Factors controlling the expressed activity of histidine ammonia-lyase in the epidermis and the resulting accumulation of urocanic acid

1981 ◽  
Vol 194 (3) ◽  
pp. 829-838 ◽  
Author(s):  
I R Scott
Keyword(s):  
Stratum Corneum ◽  
Living Cells ◽  
Urocanic Acid ◽  
Residual Protein ◽  
Thickness Skin ◽  
Lyase Activity ◽  
Part Thickness ◽  
Natural Acidity ◽  
Marked Dependence ◽  
Skin Samples

The synthesis of urocanic acid by histidine ammonia-lyase in guinea-pig epidermis was investigated in various ways. 1. In epidermal homogenates the enzyme obeys Michaelis-Menten kinetics and shows marked dependence of its activity of pH, such that below pH 6 it is inactive. 2. Part-thickness skin samples cultured with radioactive histidine do not accumulate detectable radioactive urocanic acid during 3 days in culture. 3. Very little histidine ammonia-lyase activity can be detected in the living cells of the epidermis. The enzyme is almost completely restricted to the dead cells of the stratum corneum. 4. Radioactive histidine injected into living animals does not result immediately in the accumulation of radioactive urocanic acid. By 3 days after the injection, however, both radioactive urocanic acid and histidine appear, apparently at the expense of radioactive proteins, 5. In isolated stratum corneum, the residual histidine can be converted into urocanic acid by the histidine ammonia-lyase in the tissue only if the natural acidity of the tissue is neutralized. It is concluded from these observations that the biosynthesis of urocanic acid occurs naturally only in the stratum corneum, which contains only dead cells. The amount of urocanic acid accumulated is limited by the availability of free histidine produced by proteolysis of residual protein in these cells and by the penetration into the stratum corneum of the ‘acid mantle’ of the skin.

scholarly journals Is the Filaggrin–Histidine–Urocanic Acid Pathway Essential for Stratum Corneum Acidification?

2010 ◽  
Vol 130 (8) ◽  
pp. 2141-2144 ◽  
Author(s):  
Joachim W. Fluhr ◽  
Peter M. Elias ◽  
Mao-Qiang Man ◽  
Melanie Hupe ◽  
Clare Selden ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Urocanic Acid ◽  
Acid Pathway
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