PMID- 1946209
OWN - NLM
STAT- MEDLINE
DCOM- 19911205
LR  - 20191022
IS  - 0893-5785 (Print)
IS  - 0893-5785 (Linking)
VI  - 4
IP  - 2
DP  - 1991 Mar
TI  - After dopachrome?
PG  - 53-62
AB  - Dopachrome, an intermediate in melanin biosynthesis, exhibits some unusual 
      properties. At physiologic pH (e.g., pH 6-8) it is unstable and spontaneously 
      loses its carboxyl group to form 5,6-dihydroxyindole (DHI) and CO2. However, over 
      this same pH range, if various metals or a melanocyte-specific enzyme are 
      present, it rapidly rearranges to its isomer 
      form--5,6-dihydroxyindole-2-carboxylic acid (DHICA)--which is far more stable 
      than dopachrome in its ability to retain the carboxyl group. Whether or not the 
      carboxyl group is retained could have important implications for the regulation 
      of melanogenesis, since in the presence of oxygen DHI spontaneously forms a black 
      precipitate, whereas DHICA forms a golden-brown solution. The solubility of 
      "DHICA-melanin" is due to the presence of carboxyl groups, which provide negative 
      charges and hydrophilicity. Thus, in vivo, the extent to which dopachrome is 
      converted to DHI or DHICA may well influence the solubility and color of the 
      melanin formed. The purpose of this article is to review recent findings in these 
      areas and to discuss the possible significance of dopachrome conversion in the 
      regulation of melanogenesis and color formation.
FAU - Pawelek, J M
AU  - Pawelek JM
AD  - Department of Dermatology, Yale University School of Medicine, New Haven, 
      Connecticut 06510.
LA  - eng
PT  - Journal Article
PT  - Review
PL  - Denmark
TA  - Pigment Cell Res
JT  - Pigment cell research
JID - 8800247
RN  - 0 (Indolequinones)
RN  - 0 (Indoles)
RN  - 0 (Melanins)
RN  - 0 (Quinones)
RN  - 3571-34-4 (dopachrome)
RN  - 4790-08-3 (5,6-dihydroxy-2-indolylcarboxylic acid)
RN  - EC 5.- (Isomerases)
RN  - Z3OC8499KG (5,6-dihydroxyindole)
SB  - IM
CIN - Pigment Cell Res. 1991 Dec;4(5-6):255-6. PMID: 1823931
MH  - Animals
MH  - Cell Fractionation
MH  - Enzyme Activation
MH  - *Indolequinones
MH  - Indoles/*metabolism
MH  - Isomerases/chemistry
MH  - Melanins/*biosynthesis
MH  - Melanocytes/*enzymology
MH  - Melanoma/enzymology
MH  - Pigmentation/*physiology
MH  - Quinones/*metabolism
MH  - Tumor Cells, Cultured
RF  - 65
EDAT- 1991/03/01 00:00
MHDA- 1991/03/01 00:01
CRDT- 1991/03/01 00:00
PHST- 1991/03/01 00:00 [pubmed]
PHST- 1991/03/01 00:01 [medline]
PHST- 1991/03/01 00:00 [entrez]
AID - 10.1111/j.1600-0749.1991.tb00315.x [doi]
PST - ppublish
SO  - Pigment Cell Res. 1991 Mar;4(2):53-62. doi: 10.1111/j.1600-0749.1991.tb00315.x.