Haemolysis induced by tyrosine crystals: Modifiers and inhibitors.

Tyrosine as a solid, but not in solution, caused human erythrocyte haemolysis. Haemolysis was increased with higher tyrosine concentrations and extended incubation times; it was greater at 37degrees than 4degreesC, and decreased by higher erythrocyte concentrations. Titration of phenolic groups on the surface of di-iodotyrosine crystals altered the extent of di-iodotyrosine-induced haemolysis.

Tubuloreticular inclusions in neonatal lupus erythematosus.

Numerous tubuloreticular structures were seen on electron microscopic examination of involved and uninvolved skin of a neonate with lupus erythematosus. The patient had characteristic lupus skin lesions at birth that worsened for three months, and then gradually subsided. Their course was associated with systemic illness.

Serine biosynthesis in human hair follicles by the phosphorylated pathway: follicular 3-phosphoglycerate dehydrogenase.

The phosphorylated pathway of serine biosynthesis was demonstrated in human hair bulbs and sheaths by the formation of phosphoserine and serine from (14C)3-phosphoglyceric acid. The initial and rate limiting enzyme of the pathway, 3-phosphoglycerate dehydrogenase (3-PGDH) was demonstrated by enzyme determinations in human and rat hair follicles, human epidermis, and chicken epidermis. Follicular 3-PGDH was characterized using a sensitive fluorometric assay with NADH as a co-substrate.

Molecular mechanisms of genetic disorders of keratinization.

An attempt is made to organize our current knowledge about genetically determined disorders of keratinized tissue, which primarily affect the epidermal structural proteins. Type I defects are those involving a change in a single amino acid and are analogous to sickle cell anemia. Type II defects are associated with abnormal retention of a normal structural protein intermediate.

The fibrous proteins in various types of ichthyosis.

The stratum corneum of individuals with ichthyosis vulgaris, sex-linked ichthyosis, lamellar ichthyosis, and epidermolytic hyperkeratosis has been studied. An alpha x-ray diffraction pattern has been observed in all specimens and the solubility of the alpha fibrous proteins appears to be the same as in normal stratum corneum. Sodium dodecyl sulfate (SDS)-polyacrylamide electrophoresis of the fibrous proteins showed variable patterns within the different types of ichthyosis, while amino acid analyses of the proteins were quite similar to those from normal stratum corneum.

Human epidermal transamidase.

The possible presence of epsilon-(gamma-glutamyl) lysine covalent bonds in human epidermal proteins prompted a study of transamidase activity in human hair-free epidermis. Callus contains an enzyme which catalyzes the incorporation of radioactive putrescine into alpha-casein. The enzyme is active without prior treatment with exogenous proteolytic enzymes.

The polypeptide composition of epidermal prekeratin.

An alpha-fibrous protein, prekeratin, has been isolated from cow snout epidermis with citrate buffer, pH 2.65. Using acrylamide electrophoresis with 0.