Water-Soluble Organic Components of Psoriatic Scales

Flesch, Peter; Hodgson, Courtney; Esoda, Elizabeth C. Jackson

doi:10.1001/archderm.1962.01590040040004

Cited by 24 publications

(3 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thirdly, the completeness of the breakdown of available protein in the stratum corneum to amino acids will also affect the availability of histidine. Normally such breakdown is very efficient, leaving little residual soluble protein, but under abnormal conditions of rapid epidermal growth considerable quantities of soluble protein may persist in the stratum corneum (Flesch & Jackson, 1962). Fourthly, the time available for the histidase to act after the cell membranes become impermeable, but before the cells become too acidic for the enzyme to be active, will determine the efficiency with which the available histidine is converted into urocanic acid.…”

Section: Discussionmentioning

confidence: 99%

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

Scott¹

1981

Biochemical Journal

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

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

Scott¹

1981

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…Further details on the nucleic acid content were revealed by photometric determinations both of the pentose concentration [2,5,22] and phosphate content [1,23] using aqueous extracts of psoriatic scales. In addition, determinations of the free purine nitrogen according to Kjeldahl were carried out [1], These results are of no stringent significance because other sugars, nitrogen and phosphate containing substances as metabolic intermediates are present in aqueous extracts [3,16].Wheatley and F arber [24,25], Hodgson [6], Liss and Lever [12] and Lever and Liss [11] have isolated the nucleic acids from scales and analyzed their base composition. We have tried to fractionate the nucleic acids and the amount of RNA and DNA.…”

mentioning

confidence: 99%

Studies on the Species, Amount and Base Composition of Nucleic Acids in Psoriatic Scales and Normal Horny Layer

Peter¹,

Brand²,

Peter³

1975

Dermatology

View full text Add to dashboard Cite

The amount of RNA as well as DNA is considerably increased in psoriatic scales as compared with normal horny layer; RNA was characterized as a low-molecular tRNA; as concerns the base composition of DNA, no particularities in comparison with other DNA species were found, and the base composition of tRNA revealed that cytosine and guanosine are in excess; pseudouridine could not be detected in psoriatic tRNA.

show abstract

“…Voorhees et al (19) demonstrated that the histidine-rich protein synthesis did not occur in psoriatic epidermis. A few keratohyalin granules in psoriatic epidermis have been observed, and a small amount of free amino acids in psoriatic scales are known (4,5). Further investigations of the mechanisms of synthesis, conversion, and degradation of histidine-rich protein will elucidate the reduction of free amino acids of the stratum corneum observed in hyperkeratotic epidermis, in which keratohyalin granules are normally formed or rather increased.…”

Section: Discussionmentioning

confidence: 98%

Histidine-Rich Protein as a Possible Origin of Free Amino Acids of Stratum Corneum

Horii

Kawasaki

Koyama

et al.

Current Problems in Dermatology

View full text Add to dashboard Cite

Pulse-chase labeling experiments with 5H-histidine and 5H-arginine were performed in hairless mice to investigate the origin of free amino acids in the stratum corneum. Time-course labeling of epidermal proteins was examined by sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE). The radioactivity was also measured in the following three epidermal fractions; O.IN HCI04 soluble-ethanol soluble fraction (Fr. I), 0.1 N HCI0 4 soluble-ethanol insoluble fraction (Fr. II, histidine-rich protein fraction) and 0.1 N HCI0 4 insoluble-8M urea soluble fraction (Fr. III).Labeled amino acids were rapidly incorporated into Fr. III, especially into a particular protein which showed little mobility on SDS-PAGE. As the radioactivity of this protein decreased, an increase in radioactivity was observed in a 32,000 MW histidine-rich protein, the only major protein in Fr. II. The radioactivity of 32,000 MW protein then fell, accompanied by an increase in radioactivity of Fr. I. The major radioactive substances in Fr. I were identified as 5H-histidine and 5Hurocanic acid after 5H-histidine injection and as 5H-arginine after 5H-arginine injection. The amino"acid composition of the histidine-rich protein was very similar to the composition of free amino acids of the stratum corneum, in which amino acid metabolites were considered as their precursor amino acids.These results suggested that the free amino acids of the stratum corneum might be a final product of the degradation of histidine-rich protein.

show abstract

Water-Soluble Organic Components of Psoriatic Scales

Cited by 24 publications

References 45 publications

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

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

Studies on the Species, Amount and Base Composition of Nucleic Acids in Psoriatic Scales and Normal Horny Layer

Histidine-Rich Protein as a Possible Origin of Free Amino Acids of Stratum Corneum

Contact Info

Product

Resources

About