PMID- 10231199
OWN - NLM
STAT- MEDLINE
DCOM- 19990723
LR  - 20191024
IS  - 0893-5785 (Print)
IS  - 0893-5785 (Linking)
VI  - 12
IP  - 2
DP  - 1999 Apr
TI  - Insect melanogenesis. II. Inability of Manduca phenoloxidase to act on 
      5,6-dihydroxyindole-2-carboxylic acid.
PG  - 118-25
AB  - Eumelanins in animals are biosynthesized by the combined action of tyrosinase, 
      3,4-dihydroxyphenylalanine (DOPA)chrome isomerase, and other factors. Two kinds 
      of eumelanins were characterized from mammalian systems; these are 
      5,6-dihydroxyindole (DHI)-melanin and 5,6-dihydroxyindole-2-carboxylic acid 
      (DHICA)-melanin. In insects, melanin biosynthesis is initiated by phenoloxidase 
      and supported by DOPAchrome isomerase (decarboxylating). Based on the facts that 
      DOPA is a poor substrate for insect phenoloxidases and DHI is the sole product of 
      insect DOPAchrome isomerase reaction, it is proposed that insects lack 
      DHICA-melanin. Accordingly, the phenoloxidase isolated from the hemolymph of 
      Manduca sexta failed to oxidize DHICA. Control experiments reveal that mushroom 
      tyrosinase, as well as laccase, which is a contaminant in the commercial 
      preparations of mushroom tyrosinase, are capable of oxidizing DHICA. Neither the 
      whole hemolymph nor the cuticular extracts of M. sexta possessed any detectable 
      oxidase activity towards this substrate. Thus, insects do not seem to produce 
      DHICA-eumelanin. A useful staining procedure to localize DHICA oxidase activity 
      on gels is also presented.
FAU - Sugumaran, M
AU  - Sugumaran M
AD  - Department of Biology, University of Massachusetts at Boston, 02125, USA. 
      manickam.sugumaran@umb.edu
FAU - Duggaraju, R
AU  - Duggaraju R
FAU - Generozova, F
AU  - Generozova F
FAU - Ito, S
AU  - Ito S
LA  - eng
GR  - R01-AI-14753/AI/NIAID NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Denmark
TA  - Pigment Cell Res
JT  - Pigment cell research
JID - 8800247
RN  - 0 (Indoles)
RN  - 0 (Melanins)
RN  - 4790-08-3 (5,6-dihydroxy-2-indolylcarboxylic acid)
RN  - EC 1.14.18.1 (Monophenol Monooxygenase)
SB  - IM
MH  - Animals
MH  - Indoles/*metabolism
MH  - Manduca/*enzymology
MH  - Melanins/*metabolism
MH  - Molecular Structure
MH  - Monophenol Monooxygenase/*metabolism
EDAT- 1999/05/07 00:00
MHDA- 1999/05/07 00:01
CRDT- 1999/05/07 00:00
PHST- 1999/05/07 00:00 [pubmed]
PHST- 1999/05/07 00:01 [medline]
PHST- 1999/05/07 00:00 [entrez]
AID - 10.1111/j.1600-0749.1999.tb00751.x [doi]
PST - ppublish
SO  - Pigment Cell Res. 1999 Apr;12(2):118-25. doi: 10.1111/j.1600-0749.1999.tb00751.x.