cysteinyldopa

Summary

Summary: Found in large amounts in the plasma and urine of patients with malignant melanoma. It is therefore used in the diagnosis of melanoma and for the detection of postoperative metastases. Cysteinyldopa is believed to be formed by the rapid enzymatic hydrolysis of 5-S-glutathionedopa found in melanin-producing cells.

Top Publications

  1. Dizdar N, Kullman A, Kagedal B, Arstrand K. Effects on interstitial glutathione, cysteine and 5-S-cysteinyldopa of buthionine sulphoximine in human melanoma transplants. Melanoma Res. 1997;7:322-8 pubmed
    ..The cysteine concentrations also decreased, while 5-S-cysteinyldopa tended to increase during BSO treatment...
  2. Kärnell R, von Schoultz E, Hansson L, Nilsson B, Arstrand K, Kagedal B. S100B protein, 5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid as biochemical markers for survival prognosis in patients with malignant melanoma. Melanoma Res. 1997;7:393-9 pubmed
    Elevated levels of the phaeomelanin metabolite 5-S-cysteinyldopa and the eumelanin metabolite 6-hydroxy-5-methoxyindole-2-carboxylic acid in urine and serum have been shown in previous studies to correlate with disseminated malignant ..
  3. Shikuma K, Omasa M, Yutaka Y, Okuda M, Taki T. Treatment of primary melanoma of the lung monitored by 5-S-cysteinyldopa levels. Ann Thorac Surg. 2009;87:1264-6 pubmed publisher
    ..5-S-Cysteinyldopa (5-S-CD), a melanin metabolite, has been reported to be a prognostic marker for cutaneous malignant melanoma...
  4. Hasegawa M, Takata M, Hatta N, Wakamatsu K, Ito S, Takehara K. Simultaneous measurement of serum 5-S-cysteinyldopa, circulating intercellular adhesion molecule-1 and soluble interleukin-2 receptor levels in Japanese patients with malignant melanoma. Melanoma Res. 1997;7:243-51 pubmed
  5. Hirai S, Kageshita T, Kimura T, Tsujisaki M, Imai K, Wakamatsu K, et al. Serum levels of sICAM-1 and 5-S-cysteinyldopa as markers of melanoma progression. Melanoma Res. 1997;7:58-62 pubmed
    The serum levels of the soluble form of intercellular adhesion molecule-1 (sICAM-1) and 5-S-cysteinyldopa (5-S-CD) were determined by double determinant immunoassay and high-performance liquid chromatography, respectively...
  6. Bánfalvi T, Boldizsár M, Gergye M, Gilde K, Kremmer T, Otto S. Comparison of prognostic significance of serum 5-S-Cysteinyldopa, LDH and S-100B protein in Stage III-IV malignant melanoma. Pathol Oncol Res. 2002;8:183-7 pubmed
    5-S-cysteinyldopa is a precursor of pheomelanin. S-100B protein is a low molecular weight, acidic, calcium binding, cytoplasmatic protein. LDH was defined as the most important serum parameter in disseminated melanoma...
  7. Wimmer I, Meyer J, Seifert B, Dummer R, Flace A, Burg G. Prognostic value of serum 5-S-cysteinyldopa for monitoring human metastatic melanoma during immunochemotherapy. Cancer Res. 1997;57:5073-6 pubmed
    The melanin metabolite 5-S-cysteinyldopa (5-S-CD) has been reported to be helpful in detecting occult melanoma metastases and as a prognostic marker in B16 melanoma-bearing mice...
  8. Kärnell R, Kagedal B, Lindholm C, Nilsson B, Arstrand K, Ringborg U. The value of cysteinyldopa in the follow-up of disseminated malignant melanoma. Melanoma Res. 2000;10:363-9 pubmed
    In a series of 92 patients with malignant melanoma, clinical stage III or IV, both 5-S-cysteinyldopa (5SCD) and 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI2C) were measured in urine during chemotherapy...
  9. Di Donato P, Napolitano A, Prota G. Metal ions as potential regulatory factors in the biosynthesis of red hair pigments: a new benzothiazole intermediate in the iron or copper assisted oxidation of 5-S-cysteinyldopa. Biochim Biophys Acta. 2002;1571:157-66 pubmed
    In the presence of iron or copper ions, the course of the oxidation in air of 5-S-cysteinyldopa (1), the main biosynthetic precursor of pheomelanins and trichochromes, was markedly changed affording two main products...

More Information

Publications62

  1. Costantini C, d Ischia M, Palumbo A, Prota G. Photochemistry of 5-S-cysteinyldopa. Photochem Photobiol. 1994;60:33-7 pubmed
    The photochemical behavior of 5-S-cysteinyldopa (5-S-CD), a colorless product of melanocyte metabolism, was investigated in neutral phosphate buffer with biologically relevant UV radiation...
  2. Bánfalvi T, Gilde K, Boldizsár M, Kremmer T, Otto S. Serum levels of S-100 protein and 5-S-cysteinyldopa as markers of melanoma progression. Pathol Oncol Res. 1999;5:218-22 pubmed
    Serum S-100 protein is widely used as a marker of melanoma and since 5-S-cysteinyldopa (5-S-CD) is a precursor of melanin its serum and urinary levels can reflect melanoma progression...
  3. Wakamatsu K, Ohtara K, Ito S. Chemical analysis of late stages of pheomelanogenesis: conversion of dihydrobenzothiazine to a benzothiazole structure. Pigment Cell Melanoma Res. 2009;22:474-86 pubmed publisher
    ..3,4-dihydroxyphenylalanine) by tyrosinase in the presence of cysteine, which results in the production of 5-S-cysteinyldopa and its isomers...
  4. Bánfalvi T, Gilde K, Boldizsár M, Fejos Z, Horvath B, Liszkay G, et al. Serum concentration of 5-S-cysteinyldopa in patients with melanoma. Eur J Clin Invest. 2000;30:900-4 pubmed
    5-S-cysteinyldopa (5-S-DC) is a precursor of melanin. Its serum and urinary level can reflect melanoma progression...
  5. Tardy J, Barrois J, Bendelac A, Leonard F, Triller R, Jardillier J, et al. Urinary excretion of 5-S-cysteinyldopa is enhanced by PUVA and is independent of skin type. Photodermatol. 1987;4:205-8 pubmed
    Urinary excretion of 5-S-cysteinyldopa (5-S-CD) was followed in 20 patients receiving PUVA therapy. Large increases were observed after PUVA treatment, more predominant in males and unrelated to skin types...
  6. Yoshida Y, Furumura M, Tahira M, Horie T, Yamamoto O. Serum biomarker in neurofibromatosis type 1. J Dermatol Sci. 2012;67:155-8 pubmed publisher
  7. Dagnino Subiabre A, Cassels B, Baez S, Johansson A, Mannervik B, Segura Aguilar J. Glutathione transferase M2-2 catalyzes conjugation of dopamine and dopa o-quinones. Biochem Biophys Res Commun. 2000;274:32-6 pubmed
    ..Both conjugates were found to be resistant to oxidation by biological oxidizing agents such as O(2), H(2)O(2), and O(*-)(2), and the glutathione transferase-catalyzed reaction can therefore serve a neuroprotective antioxidant function...
  8. Shinno K, Nagahiro S, Uno M, Kannuki S, Nakaiso M, Sano N, et al. Neurocutaneous melanosis associated with malignant leptomeningeal melanoma in an adult: clinical significance of 5-S-cysteinyldopa in the cerebrospinal fluid---case report. Neurol Med Chir (Tokyo). 2003;43:619-25 pubmed
    ..Combined chemoimmunotherapy was repeated every other month with monitoring of the 5-S-cysteinyldopa (5-S-CD) level in the cerebrospinal fluid (CSF)...
  9. Hu F, Woodward W, Peterson L. Plasma 5-S-cysteinyldopa correlates with tumor size in melanoma-bearing mice. J Invest Dermatol. 1988;90:149-51 pubmed
    ..high performance liquid chromatography with electrochemical detection (HPLC-ED) was used to compare 5-S-cysteinyldopa (CD) levels in plasma to tumor size in a murine melanoma model system...
  10. Wolber R, Schlenz K, Wakamatsu K, Smuda C, Nakanishi Y, Hearing V, et al. Pigmentation effects of solar-simulated radiation as compared with UVA and UVB radiation. Pigment Cell Melanoma Res. 2008;21:487-91 pubmed publisher
    ..Levels of free 5-S-cysteinyldopa (5SCD) were elevated about 4-fold in SSR- or UVB-exposed skin compared with UVA-exposed or control skin...
  11. Schmitz S, Thomas P, Allen T, Poznansky M, Jimbow K. Dual role of melanins and melanin precursors as photoprotective and phototoxic agents: inhibition of ultraviolet radiation-induced lipid peroxidation. Photochem Photobiol. 1995;61:650-5 pubmed
    ..in the presence of eumelanin, pheomelanin and two of their major precursors, 5,6-dihydroxyindole (DHI) and 5-S-cysteinyldopa (SCD)...
  12. Goto H, Tenou T, Kudo H, Iwasaki T, Muramatsu R, Usui M, et al. [5-S-cysteinyldopa as a tumor marker for primary uveal malignant melanoma]. Nippon Ganka Gakkai Zasshi. 1998;102:319-26 pubmed
    The clinical significance of 5-S-cysteinyldopa (5-S-CD), a major intermediate in melanin synthesis, was evaluated as a potential diagnostic tumor marker for uveal melanoma...
  13. Blomquist L, Dizdar N, Karlsson M, Kagedal B, Ossowicki H, Pettersson A, et al. Microdialysis of 5-S-cysteinyldopa from interstitial fluid in cutaneous human melanoma transplanted to athymic mice. Melanoma Res. 1991;1:23-32 pubmed
    ..investigated as a tool for the determination of the extracellular concentration of the pigment metabolite 5-S-cysteinyldopa in human melanoma transplanted to athymic mice...
  14. Karg E, Odh G, Rosengren E, Wittbjer A, Rorsman H. Melanin-related biochemistry of IGR 1 human melanoma cells. Melanoma Res. 1991;1:5-13 pubmed
    ..IGR 1 cells contain large amounts of 5-S-cysteinyldopa which is the quantitatively most important catecholic amino acid...
  15. Carstam R, Brinck C, Fornstedt B, Rorsman H, Rosengren E. 5-S-cysteinyldopac in human urine. Acta Derm Venereol. 1990;70:373-7 pubmed
    ..The findings give further evidence for a small but significant non-specific oxidation of endogenous catechol derivatives in vivo, a fact to be considered when using 5-S-cysteinyldopa as a measure of pigment metabolism.
  16. Saito N, Morishima T. [Eumelanin and pheomelanin contents in hairs of healthy Japanese and patients with oculocutaneous albinism, and 5-S-cysteinyldopa and 5-hydroxy-6-methoxyindole-2-carboxylic acid levels in urine of oculocutaneous albinism]. Nihon Hifuka Gakkai Zasshi. 1990;100:853-61 pubmed
    ..The urinary 5-S-Cysteinyldopa (5-S-CD) and 5-Hydroxy-6-Methoxyindole-2-Carboxylic acid (5H6MI2C) contents in the 4 albino subjects were also ..
  17. Jin K, Nogita T, Toyoda H, Kawashima M, Hidano A. Pedunculated pigmented eccrine poroma of the scalp with increased urinary excretion of 5-S-cysteinyldopa. J Dermatol. 1990;17:555-8 pubmed
    ..Initially, the urinary excretion level of 5-S-cysteinyldopa (5-S-CD) was high, but, after resection of the tumor, the level of 5-S-CD returned to normal.
  18. Stierner U, Rosdahl I, Augustsson A, Kagedal B. Urinary excretion of 5-S-cysteinyldopa in relation to skin type, UVB-induced erythema, and melanocyte proliferation in human skin. J Invest Dermatol. 1988;91:506-10 pubmed
    5-S-Cysteinyldopa (5-S-CD) is found in all pigment-producing cells and is the major precursor of phaeomelanin. However, the melanocyte specificity of the compound has been questioned...
  19. Bánfalvi T, Gilde K, Boldizsár M, Kremmer T. Clinical significance of 5-S-cysteinyldopa monitoring in patients with malignant melanoma. Neoplasma. 2002;49:121-5 pubmed
    5-S-cysteinyldopa is a precursor of melanin. Its serum and urinary level can reflect melanoma progression...
  20. Kvam E, Dahle J. The pheomelanin precursor 5-S-cysteinyldopa protects melanocytes from membrane damage induced by ultraviolet A radiation. Cancer Lett. 2005;221:131-4 pubmed
    ..The pheomelanin precursor, 5-S-cysteinyldopa, has been shown to sensitise DNA to oxidative damage by ultraviolet radiation...
  21. Takasaki A, Nezirević D, Arstrand K, Wakamatsu K, Ito S, Kagedal B. HPLC analysis of pheomelanin degradation products in human urine. Pigment Cell Res. 2003;16:480-6 pubmed
    ..5-S-Cysteinyldopa-derived benzothiazine products give 4-AHP while 2-S-cysteinyldopa-derived benzothiazine products give 3-AHP...
  22. Mosca L, Tempera I, Lendaro E, Di Francesco L, D Erme M. Characterization of catechol-thioether-induced apoptosis in human SH-SY5Y neuroblastoma cells. J Neurosci Res. 2008;86:954-60 pubmed
    ..Overall, our data support the hypothesis that CysDA may induce apoptotic death in neuronal cells, via an initial perturbation of calcium homeostasis in the cytosol...
  23. Land E, Riley P. Spontaneous redox reactions of dopaquinone and the balance between the eumelanic and phaeomelanic pathways. Pigment Cell Res. 2000;13:273-7 pubmed
    ..a Michael addition of the side-chain amino group takes place; or (2) a reductive addition of cysteine to give cysteinyldopa. In the former case, the product cyclodopa, is known rapidly to undergo a redox exchange reaction with ..
  24. Bánfalvi T, Gilde K, Gergye M, Boldizsár M, Kremmer T, Otto S. Use of serum 5-S-CD and S-100B protein levels to monitor the clinical course of malignant melanoma. Eur J Cancer. 2003;39:164-9 pubmed
    5-S-Cysteinyldopa (5-S-CD) is a precursor of pheomelanin. S-100B protein is a low molecular weight, acidic, calcium binding, cytoplasmic protein...
  25. Jimbow K, Alena F, Dixon W, Hara H. Regulatory factors of pheo- and eumelanogenesis in melanogenic compartments. Pigment Cell Res. 1992;Suppl 2:36-42 pubmed
  26. Horikoshi T, Ito S. Serum 5-S-cysteinyldopa (5-S-CD) as a marker of melanoma progression. J Dermatol. 1992;19:809-13 pubmed
    We previously reported that serum 5-S-cysteinyldopa (5-S-CD) tended to elevate earlier and reflect melanoma progression better than urinary 5-S-CD...
  27. Fornstedt B, Bergh I, Rosengren E, Carlsson A. An improved HPLC-electrochemical detection method for measuring brain levels of 5-S-cysteinyldopamine, 5-S-cysteinyl-3,4-dihydroxyphenylalanine, and 5-S-cysteinyl-3,4-dihydroxyphenylacetic acid. J Neurochem. 1990;54:578-86 pubmed
    ..The products generated during catechol autoxidation, including quinones and reduced forms of oxygen, are known to be potentially cytotoxic...
  28. Wakamatsu K, Ito S, Fujita K. Melanin-related metabolites in urine of B16 melanoma-bearing mice. Acta Derm Venereol. 1988;68:385-9 pubmed
    5-S-Cysteinyldopa (5-S-CD), a pheomelanin precursor, has been used as a biochemical marker of melanoma metastasis...
  29. Murakami K, Nakanishi Y, Wakamatsu K, Yamamoto K, Kohriyama N, Hasegawa M, et al. Serum levels of 5-s-cysteinyldopa are correlated with skin colors in hemodialysis patients but not in peritoneal dialysis patients. Blood Purif. 2009;28:209-15 pubmed publisher
    ..We previously reported that serum levels of 5-S-cysteinyldopa (5SCD, a pheomelanin precursor) and pheomelanin were significantly elevated in HD patients.
  30. Sasaki Y, Shimizu H, Naka W, Takeshita E, Nishikawa T. Evaluation of the clinical usefulness of measuring urinary excretion of 5-S-cysteinyldopa in melanoma: ten years' experience of 50 patients. Acta Derm Venereol. 1997;77:379-81 pubmed
    The urinary excretion of 5-S-cysteinyldopa (5-S-CD) is known to be increased in certain patients with melanoma...
  31. Benathan M, Labidi F. Insulin inhibits tyrosinase activity and 5-S-cysteinyldopa formation in human melanoma cells. Acta Derm Venereol. 1997;77:281-4 pubmed
    ..001) and to a concomitant reduction in the levels of 5-S-cysteinyldopa (p <0.01)...
  32. Tesema Y, Pham D, Franz K. Counterions influence reactivity of metal ions with cysteinyldopa model compounds. Inorg Chem. 2008;47:1087-95 pubmed publisher
    ..CarboxyCydo (2-amino-3-(4,6-di-tert-butyl-2,3-dihydroxyphenylsulfanyl)-propionic acid) are model compounds of cysteinyldopa that retain its metal-binding functionalities but cannot polymerize due to the presence of blocking tert-butyl ..
  33. Wakamatsu K, Ito S. Evaluation of melanin-related metabolites as markers of solar ultraviolet-B radiation. Pigment Cell Res. 2006;19:460-4 pubmed
    ..In the present study, we measured serum and urine levels of melanin-related metabolites, 5-S-cysteinyldopa (5-S-CD) and 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI2C), in nine subjects exposed to normal ..
  34. Hanawa Y, Wakamatsu K, Ikeda S. Serum concentration of 5-S-cysteinyldopa in pediatric patients with giant pigmented nevi. J Dermatol. 1996;23:16-21 pubmed
    The serum concentrations of 5-S-cysteinyldopa (5-S-CD) in pediatric patients with giant pigmented nevi (GPN) were investigated and compared with those of pediatric patients with small- or medium-sized congenital nevi (CN), or non-..
  35. Horikoshi T, Ito S, Wakamatsu K, Onodera H, Eguchi H. Evaluation of melanin-related metabolites as markers of melanoma progression. Cancer. 1994;73:629-36 pubmed
    Urinary excretion of 5-S-cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression...
  36. Manini P, Napolitano A, d Ischia M. Reactions of D-glucose with phenolic amino acids: further insights into the competition between Maillard and Pictet-Spengler condensation pathways. Carbohydr Res. 2005;340:2719-27 pubmed
    The reactions of 5-S-cysteinyldopa, L-alpha-methyldopa and DL-m-tyrosine with D-glucose were investigated at 90 degrees C in phosphate buffer at pH ranging from 5.0 to 9.0...
  37. Hirobe T, Wakamatsu K, Ito S. Changes in the proliferation and differentiation of neonatal mouse pink-eyed dilution melanocytes in the presence of excess tyrosine. Pigment Cell Res. 2003;16:619-28 pubmed
    ..5,6-dihydroxyindole-2-carboxylic acid, as well as the contents of pheomelanin and its precursor, 5-S-cysteinyldopa in culture media from p/p melanocytes were similar to those of P/P melanocytes at all ages tested...
  38. Napolitano A, Di Donato P, Prota G. New regulatory mechanisms in the biosynthesis of pheomelanins: rearrangement vs. redox exchange reaction routes of a transient 2H-1, 4-benzothiazine-o-quinonimine intermediate. Biochim Biophys Acta. 2000;1475:47-54 pubmed
    ..path C was assessed by deuterium labeling experiments. These findings point to new mechanisms of regulation of the initial steps of pheomelanogenesis, bearing significant implications on the structure of the final pigment...
  39. Stierner U, Augustsson A, Rosdahl I, Kagedal B, Suurkula M. UVB-induced melanocyte proliferation and 5-S-cysteinyldopa excretion in dysplastic nevus syndrome. Photodermatol. 1988;5:218-23 pubmed
    ..The urinary excretion of 5-S-cysteinyldopa (5-S-CD) was measured before, during and after the irradiation period...
  40. Wakamatsu K, Ito S. Seasonal variation in serum concentration of 5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid in healthy Japanese. Pigment Cell Res. 1995;8:132-4 pubmed
    Serum concentrations of 5-S-cysteinyldopa (5-S-CD) and 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI2C) have been used as biochemical markers of melanoma progression...
  41. Ye Z, Kageshita T, Ishihara T, Ito S, Ono T. A case of malignant melanoma: disease progression correlated with serum levels of 5-S-Cysteinyldopa (5-S-CD) and intercellular adhesion molecule-1 (ICAM-1). J Dermatol. 1995;22:370-5 pubmed
    ..The serum levels of 5-S-Cysteinyldopa (5-S-CD) and intercellular adhesion molecule-1 (ICAM-1) correlated with the disease progression...
  42. Spencer J, Whiteman M, Jenner P, Halliwell B. 5-s-Cysteinyl-conjugates of catecholamines induce cell damage, extensive DNA base modification and increases in caspase-3 activity in neurons. J Neurochem. 2002;81:122-9 pubmed
    ..Indeed, intracellular ROS were observed to rise sharply on exposure to the conjugates. These results suggest one mechanism by which oxidative stress may occur in the substantia nigra in Parkinson's disease...
  43. Magnay J, Tong J, Drangova R, Baines A. Production of cysteinyl-dopamine during intravenous dopamine therapy. Kidney Int. 2001;59:1891-8 pubmed
    ..We used cysteinyl-dopamine production as an index of thioester production during intravenous dopamine treatment of critically ill patients...
  44. Meyerhöffer S, Lindberg Z, Hager A, Kagedal B, Rosdahl I. Urinary excretion of 5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid in children. Acta Derm Venereol. 1998;78:31-5 pubmed
    5-S-Cysteinyldopa (5SCD) and 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI2C) are formed during biosynthesis of melanins...
  45. Dizdar N, Kullman A, Kagedal B. Comparison of N-acetylcysteine and l-2-oxothiazolidine-4-carboxylate as cysteine deliverers and glutathione precursors in human malignant melanoma transplants in mice. Cancer Chemother Pharmacol. 2000;45:192-8 pubmed
    ..It is therefore of importance to study interstitial concentrations in melanoma tissue while decreasing its formation with an enzyme inhibitor and increasing its amount with cysteine deliverers...
  46. Hirobe T, Takeuchi S, Hotta E, Wakamatsu K, Ito S. Pheomelanin production in the epidermis from newborn agouti mice is induced by the expression of the agouti gene in the dermis. Pigment Cell Res. 2004;17:506-14 pubmed
    ..In addition, the content of the pheomelanin precursor, 5-S-cysteinyldopa, in culture media from A/A melanocytes was dramatically increased by L-tyrosine...
  47. Tesema Y, Pham D, Franz K. Synthesis and characterization of copper(II) complexes of cysteinyldopa and benzothiazine model ligands related to pheomelanin. Inorg Chem. 2006;45:6102-4 pubmed
    A new cysteinyldopa model ligand Cydo {3-[(2-aminoethyl)sulfanyl]-4,6-di-tert-butylbenzene-1,2-diol} was prepared and its reactivity with Cu(II) explored...
  48. Shen X, Xia B, Wrona M, Dryhurst G. Synthesis, redox properties, in vivo formation, and neurobehavioral effects of N-acetylcysteinyl conjugates of dopamine: possible metabolites of relevance to Parkinson's disease. Chem Res Toxicol. 1996;9:1117-26 pubmed
    ..Methods are described for the synthesis of several N-acetylcysteinyl conjugates of DA, and their redox behaviors have been studied using cyclic voltammetry...
  49. Fornstedt B, Pileblad E, Carlsson A. In vivo autoxidation of dopamine in guinea pig striatum increases with age. J Neurochem. 1990;55:655-9 pubmed
    ..In contrast, the concentration of DOPAC increased with age: The DOPAC level in the 3-year-old animals was 153% of the level in the 2-week-old animals and 116% of the level in the 2-month-old animals.(ABSTRACT TRUNCATED AT 250 WORDS)..
  50. Sawada M, Terada N, Nishizawa Y, Ito S, Wakamatsu K, Takemura K, et al. Establishment and characterization of human vaginal malignant melanoma xenotransplants. Anticancer Res. 1994;14:1477-82 pubmed
    ..The levels of AFP, CA125 and CEA in sera of tumor-bearing mice were within normal range. The 5-S-cysteinyldopa level in sera of tumor-bearing mice correlated well with the size of the tumor...
  51. Maresca V, Flori E, Briganti S, Camera E, Cario Andre M, Taieb A, et al. UVA-induced modification of catalase charge properties in the epidermis is correlated with the skin phototype. J Invest Dermatol. 2006;126:182-90 pubmed
    ..These results demonstrate that pheomelanin could act as a photosensitizing agent, following UVA irradiation, inducing charge modifications of native catalase, by a mechanism involving singlet oxygen or its downstream products...
  52. Sato C, Ito S, Takeuchi T. Enhancement of pheomelanogenesis by L-dopa in the mouse melanocyte cell line, TM10, in vitro. J Cell Sci. 1987;87 ( Pt 4):507-12 pubmed
    ..2mM-L-dopa, an increase in the number of pheomelanosomes was observed in the cytoplasm of TM10 cells. Our results also suggest that the L-dopa treatment results in a decrease in tyrosinase activity per melanosome...
  53. Benathan M, Labidi F. Cysteine-dependent 5-S-cysteinyldopa formation and its regulation by glutathione in normal epidermal melanocytes. Arch Dermatol Res. 1996;288:697-702 pubmed
    Recent evidence suggests that the melanogenesis intermediate 5-S-cysteinyldopa (5-S-CD) could display antioxidative activity...