PMID- 10611283
OWN - NLM
STAT- MEDLINE
DCOM- 20000127
LR  - 20190501
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 96
IP  - 26
DP  - 1999 Dec 21
TI  - Identification of a cytochrome b-type NAD(P)H oxidoreductase ubiquitously
      expressed in human cells.
PG  - 14742-7
AB  - Cytochrome b-type NAD(P)H oxidoreductases are involved in many physiological
      processes, including iron uptake in yeast, the respiratory burst, and perhaps
      oxygen sensing in mammals. We have identified a cytosolic cytochrome b-type
      NAD(P)H oxidoreductase in mammals, a flavohemoprotein (b5+b5R) containing
      cytochrome b5 (b5) and b5 reductase (b5R) domains. A genetic approach, using
      BLAST searches against DBEST for FAD-, NAD(P)H-binding sequences followed by
      reverse transcription-PCR, was used to clone the complete cDNA sequence of human 
      b5+b5R from the hepatoma cell line Hep 3B. Compared with the classical
      single-domain b5 and b5R proteins localized on endoplasmic reticulum membrane,
      b5+b5R also has binding motifs for heme, FAD, and NAD(P)H prosthetic groups but
      no membrane anchor. The human b5+b5R transcript was expressed at similar levels
      in all tissues and cell lines that were tested. The two functional domains b5*
      and b5R* are linked by an approximately 100-aa-long hinge bearing no sequence
      homology to any known proteins. When human b5+b5R was expressed as c-myc adduct
      in COS-7 cells, confocal microscopy revealed a cytosolic localization at the
      perinuclear space. The recombinant b5+b5R protein can be reduced by NAD(P)H,
      generating spectrum typical of reduced cytochrome b with alpha, beta, and Soret
      peaks at 557, 527, and 425 nm, respectively. Human b5+b5R flavohemoprotein is a
      NAD(P)H oxidoreductase, demonstrated by superoxide production in the presence of 
      air and excess NAD(P)H and by cytochrome c reduction in vitro. The properties of 
      this protein make it a plausible candidate oxygen sensor.
FAU - Zhu, H
AU  - Zhu H
AD  - Hematology Division, Brigham and Women's Hospital, Harvard Medical School, 221
      Longwood Avenue, Boston, MA 02115, USA.
FAU - Qiu, H
AU  - Qiu H
FAU - Yoon, H W
AU  - Yoon HW
FAU - Huang, S
AU  - Huang S
FAU - Bunn, H F
AU  - Bunn HF
LA  - eng
SI  - GENBANK/AF169481
SI  - GENBANK/AF169802
SI  - GENBANK/AF169803
GR  - R01 DK41234/DK/NIDDK NIH HHS/United States
GR  - K01 DK059901/DK/NIDDK NIH HHS/United States
GR  - F32 DK09678/DK/NIDDK NIH HHS/United States
GR  - F32 DK009678-03/DK/NIDDK NIH HHS/United States
GR  - F32 DK009678-01/DK/NIDDK NIH HHS/United States
GR  - R01 DK041234/DK/NIDDK NIH HHS/United States
GR  - F32 DK009678/DK/NIDDK NIH HHS/United States
GR  - F32 DK009678-02/DK/NIDDK NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Flavoproteins)
RN  - 0 (Hemeproteins)
RN  - 0 (Neoplasm Proteins)
RN  - 0 (Recombinant Fusion Proteins)
RN  - 9035-39-6 (Cytochromes b5)
RN  - EC 1.6.- (NADH, NADPH Oxidoreductases)
RN  - EC 1.6.2.- (Cytochrome Reductases)
RN  - EC 1.6.2.2 (Cytochrome-B(5) Reductase)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Amino Acid Sequence
MH  - Cell Compartmentation
MH  - Cytochrome Reductases/*genetics
MH  - Cytochrome-B(5) Reductase
MH  - Cytochromes b5/*genetics
MH  - Cytosol/enzymology
MH  - Flavoproteins/genetics
MH  - Gene Expression
MH  - Hemeproteins/genetics
MH  - Humans
MH  - Models, Biological
MH  - Molecular Sequence Data
MH  - NADH, NADPH Oxidoreductases/*genetics
MH  - Neoplasm Proteins/genetics
MH  - Oxygen/metabolism
MH  - Protein Structure, Tertiary
MH  - Recombinant Fusion Proteins/genetics
MH  - Sequence Homology, Amino Acid
MH  - Signal Transduction
MH  - Tissue Distribution
PMC - PMC24718
EDAT- 1999/12/28 00:00
MHDA- 1999/12/28 00:01
CRDT- 1999/12/28 00:00
PHST- 1999/12/28 00:00 [pubmed]
PHST- 1999/12/28 00:01 [medline]
PHST- 1999/12/28 00:00 [entrez]
AID - 10.1073/pnas.96.26.14742 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 1999 Dec 21;96(26):14742-7. doi:
      10.1073/pnas.96.26.14742.