Evidence map›Paper›PMID 26663892›Full record

ReviewJournal of thrombosis and haemostasis : JTH2016

Structural and functional insights into enzymes of the vitamin K cycle.

J-K Tie, D W Stafford

Open access · bronzeAbstract readReview
In one paragraph

Review in Journal of thrombosis and haemostasis : JTH, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 68 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
68citing papers in PubMed, 1 pooled it
7.8field-weighted citation impact, top 2% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

68 citing papers in PubMed, 1 synthesis or guideline pooled it, 120 citations in OpenAlex.

  1. Pooled it
  2. Review
  3. Oxidative protein folding and CaCellular and molecular life sciences : CMLS · 2026
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  10. Integrative phytochemical profiling andFrontiers in nutrition · 2026
    Article
  11. Review
  12. Article
  13. Article
  14. Predictor Role ofMedicina (Kaunas, Lithuania) · 2025
    Article
  15. Review
  16. Review
  17. Article
  18. Review
  19. Article
  20. Review

8 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors at 1 institution in 1 country.

J-K TieDepartment of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
D W StaffordDepartment of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
University of North Carolina at Chapel Hill · US

Funding

Characterization of enzymes in the vitamin K cycleR01HL131690 · NHLBI · UNIV OF NORTH CAROLINA CHAPEL HILL · PI STAFFORD, DARREL W, TIE, JIANKE · 2016 to 2023
$4.0M
Characterization of Vitamin K Epoxide ReductaseR01HL077740 · NHLBI · UNIV OF NORTH CAROLINA CHAPEL HILL · PI STAFFORD, DARREL W, TIE, JIANKE · 2005 to 2015
$3.9M
NHLBI NIH HHS HL077740NHLBI NIH HHS R01 HL077740NHLBI NIH HHS R01 HL131690
6 · The paper itself

Abstract

Vitamin K-dependent proteins require carboxylation of certain glutamates for their biological functions. The enzymes involved in the vitamin K-dependent carboxylation include: gamma-glutamyl carboxylase (GGCX), vitamin K epoxide reductase (VKOR) and an as-yet-unidentified vitamin K reductase (VKR). Due to the hydrophobicity of vitamin K, these enzymes are likely to be integral membrane proteins that reside in the endoplasmic reticulum. Therefore, structure-function studies on these enzymes have been challenging, and some of the results are notably controversial. Patients with naturally occurring mutations in these enzymes, who mainly exhibit bleeding disorders or are resistant to oral anticoagulant treatment, provide valuable information for the functional study of the vitamin K cycle enzymes. In this review, we discuss: (i) the discovery of the enzymatic activities and gene identifications of the vitamin K cycle enzymes; (ii) the identification of their functionally important regions and their active site residues; (iii) the membrane topology studies of GGCX and VKOR; and (iv) the controversial issues regarding the structure and function studies of these enzymes, particularly, the membrane topology, the role of the conserved cysteines and the mechanism of active site regeneration of VKOR. We also discuss the possibility that a paralogous protein of VKOR, VKOR-like 1 (VKORL1), is involved in the vitamin K cycle, and the importance of and possible approaches for identifying the unknown VKR. Overall, we describe the accomplishments and the remaining questions in regard to the structure and function studies of the enzymes in the vitamin K cycle.

Indexed as

Blood CoagulationAmino Acid SequenceAnimalsCarbon-Carbon LigasesGene Expression Regulation, EnzymologicGenotypeHumansModels, MolecularMolecular Sequence DataNAD(P)H Dehydrogenase (Quinone)PhenotypeProtein ConformationStructure-Activity RelationshipVitamin KVitamin K Epoxide ReductasesCarbon-Carbon Ligasesglutamyl carboxylaseNAD(P)H Dehydrogenase (Quinone)Vitamin KVitamin K Epoxide Reductasesgamma-glutamyl carboxylaseintegral membrane proteinsvitamin Kvitamin K reductaseVKORC1 protein

Identifiers

PMID26663892
PMCPMC5073812
OpenAlexW2191261387

What OpenQuestion holds

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Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.