PMID- 9177734
OWN - NLM
STAT- MEDLINE
DCOM- 19970721
LR  - 20131121
IS  - 0003-2697 (Print)
IS  - 0003-2697 (Linking)
VI  - 248
IP  - 1
DP  - 1997 May 15
TI  - Chemical characterization of eumelanins with special emphasis on 
      5,6-dihydroxyindole-2-carboxylic acid content and molecular size.
PG  - 149-57
AB  - Mammalian melanins exist in two chemically distinct forms; the brown to black 
      eumelanins and the yellow to reddish pheomelanins. Eumelanins are derived from 
      copolymerization of 5,6-dihydroxyindole (DHI) and 
      5,6-dihydroxyindole-2-carboxylic acid (DHICA). Eumelanins can be quantified by 
      HPLC analysis of the oxidation product pyrrole-2,3,5-tricarboxylic acid (PTCA) 
      and by our spectrophotometric method (Sp.EM). We also developed a 
      spectrophotometric method for assaying the total amount of eu- and pheomelanins 
      by dissolving them in Soluene-350 (TM). In addition, we previously showed that 
      Sp.EM/TM and PTCA/TM ratios are significant parameters in characterizing 
      eumelanins produced in follicular melanocytes. The objectives of this study were 
      (1) to clarify the significance of Sp.EM/TM and PTCA/TM ratios in synthetic 
      eumelanins and (2) to apply these methods to characterizing natural eumelanins 
      with various DHI/ DHICA ratios and molecular sizes. The results obtained show 
      that (1) the Sp.EM/TM ratio of synthetic eumelanins increases as polymerization 
      proceeds, (2) the Sp.EM/TM and PTCA/TM ratios in copolymers of DHI and DHICA 
      correlate to the percentage content of DHICA-derived units, and (3) combination 
      of the Sp.EM/TM and PTCA/TM ratios serves to estimate the DHICA content and the 
      degree of polymerization in natural eumelanins.
FAU - Ozeki, H
AU  - Ozeki H
AD  - School of Medicine, Fujita Health University, Aichi, Japan.
FAU - Wakamatsu, K
AU  - Wakamatsu K
FAU - Ito, S
AU  - Ito S
FAU - Ishiguro, I
AU  - Ishiguro I
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Anal Biochem
JT  - Analytical biochemistry
JID - 0370535
RN  - 0 (Indoles)
RN  - 0 (Melanins)
RN  - 0 (Polymers)
RN  - 0 (Pyrroles)
RN  - 0 (Quaternary Ammonium Compounds)
RN  - 0 (Solvents)
RN  - 12627-86-0 (eumelanin)
RN  - 12778-19-7 (Soluene)
RN  - 42HK56048U (Tyrosine)
RN  - 4790-08-3 (5,6-dihydroxy-2-indolylcarboxylic acid)
RN  - 63-84-3 (Dihydroxyphenylalanine)
RN  - 945-32-4 (pyrrole-2,3,5-tricarboxylic acid)
RN  - Z3OC8499KG (5,6-dihydroxyindole)
SB  - IM
MH  - Animals
MH  - Dihydroxyphenylalanine/chemistry
MH  - Humans
MH  - Indoles/*analysis
MH  - Melanins/*chemistry
MH  - Mice
MH  - Molecular Weight
MH  - Polymers
MH  - Pyrroles/*analysis
MH  - Quaternary Ammonium Compounds
MH  - Solvents
MH  - Spectrophotometry/*methods
MH  - Tyrosine/chemistry
EDAT- 1997/05/15 00:00
MHDA- 1997/05/15 00:01
CRDT- 1997/05/15 00:00
PHST- 1997/05/15 00:00 [pubmed]
PHST- 1997/05/15 00:01 [medline]
PHST- 1997/05/15 00:00 [entrez]
AID - S0003-2697(97)92079-0 [pii]
AID - 10.1006/abio.1997.2079 [doi]
PST - ppublish
SO  - Anal Biochem. 1997 May 15;248(1):149-57. doi: 10.1006/abio.1997.2079.