PMID- 8900542
OWN - NLM
STAT- MEDLINE
DCOM- 19970102
LR  - 20181113
IS  - 1076-1551 (Print)
IS  - 1528-3658 (Electronic)
IS  - 1076-1551 (Linking)
VI  - 2
IP  - 1
DP  - 1996 Jan
TI  - The immunoregulatory mediator macrophage migration inhibitory factor (MIF) 
      catalyzes a tautomerization reaction.
PG  - 143-9
AB  - BACKGROUND: Recent studies of melanin biosynthesis have uncovered an unusual 
      enzymatic activity which converts the non-naturally occurring D-isomer of 
      2-carboxy-2,3-dihydroindole-5,6-quinone (dopachrome) into 
      5,6-dihydroxyindole-2-carboxylic acid (DHICA). The aim of the present 
      investigation was to isolate and characterize the enzyme catalyzing this 
      tautomerization reaction. MATERIALS AND METHODS: After we performed a tissue 
      survey of D-dopachrome tautomerase activity, 10 bovine lenses were homogenized 
      and used as a source of enzyme. A soluble fraction was obtained by high-speed 
      centrifugation and subjected to successive FPLC chromatography on 
      Phenyl-sepharose, Mono S cation-exchange, and Superdex gel-filtration. The 
      isolated enzyme was electrophoresed, blotted onto PVDF membrane, and the N 
      terminus analyzed by gas phase micro-sequencing. RESULTS: The protein catalyzing 
      the conversion of D-dopachrome to DHICA was purified to homogeneity in 14% yield 
      and showed a molecular weight of 12 kD when analyzed by SDS-PAGE. The first 27 
      amino acid residues of this protein were sequenced and found to be identical with 
      those of bovine macrophage migration inhibitory factor (MIF). The catalytic 
      activity of native MIF was confirmed by studies of purified recombinant human 
      MIF, which showed the same tautomerase activity. While L-dopachrome was not a 
      substrate for this reaction, the methyl esters of the L- and D-isomers were found 
      to be better substrates for MIF than D-dopachrome. CONCLUSIONS: MIF has been 
      described recently to be an anterior pituitary hormone and to be released from 
      immune cells stimulated by low concentrations of glucocorticoids. Once secreted, 
      MIF acts to control, or counter-regulate, the immunosuppressive effects of 
      glucocorticoids on the immune system. Although the tested substrate, 
      D-dopachrome, does not occur naturally, the observation that MIF has tautomerase 
      activity suggests that MIF may mediate its biological effects by an enzymatic 
      reaction. These data also offer a potential approach for the design of small 
      molecule pharmacological inhibitors of MIF that may modulate its potent 
      immunoregulatory effects in vivo.
FAU - Rosengren, E
AU  - Rosengren E
AD  - Department of Pharmacology, University Hospital, Lund, Sweden.
FAU - Bucala, R
AU  - Bucala R
FAU - Aman, P
AU  - Aman P
FAU - Jacobsson, L
AU  - Jacobsson L
FAU - Odh, G
AU  - Odh G
FAU - Metz, C N
AU  - Metz CN
FAU - Rorsman, H
AU  - Rorsman H
LA  - eng
GR  - A135931/PHS 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  - England
TA  - Mol Med
JT  - Molecular medicine (Cambridge, Mass.)
JID - 9501023
RN  - 0 (Indolequinones)
RN  - 0 (Indoles)
RN  - 0 (Macrophage Migration-Inhibitory Factors)
RN  - 0 (Quinones)
RN  - 0 (Recombinant Proteins)
RN  - 3571-34-4 (dopachrome)
RN  - 4790-08-3 (5,6-dihydroxy-2-indolylcarboxylic acid)
RN  - Z3OC8499KG (5,6-dihydroxyindole)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Cattle
MH  - Chromatography, High Pressure Liquid
MH  - Electrophoresis, Polyacrylamide Gel
MH  - *Indolequinones
MH  - Indoles/metabolism
MH  - Lens, Crystalline/chemistry/*enzymology
MH  - Macrophage Migration-Inhibitory Factors/chemistry/isolation & 
      purification/*metabolism
MH  - Molecular Sequence Data
MH  - Molecular Structure
MH  - Quinones/metabolism
MH  - Recombinant Proteins/genetics/metabolism
MH  - Sequence Alignment
MH  - Sequence Analysis
PMC - PMC2230029
EDAT- 1996/01/01 00:00
MHDA- 1996/01/01 00:01
PMCR- 1996/01/01
CRDT- 1996/01/01 00:00
PHST- 1996/01/01 00:00 [pubmed]
PHST- 1996/01/01 00:01 [medline]
PHST- 1996/01/01 00:00 [entrez]
PHST- 1996/01/01 00:00 [pmc-release]
PST - ppublish
SO  - Mol Med. 1996 Jan;2(1):143-9.