As an important subtype of the fat-soluble vitamin K2, menaquinone-7 (MK-7) plays an important role in the prevention of cardiovascular sclerosis and the treatment of osteoporosis, due to the advantages of long half-life and high biological affinity in human body. Thus, MK-7 has attracted much attention in the fields of medicine and functional food. While studies have shown that MK-7 is a component of the cell membrane and acts as an electron carrier in electron transport, there were few reports on the mechanism of MK-7 entering and leaving the cell membrane. Although 1,4-dihydroxy-2-naphthoic acid prenyl transferase MenA and methyltransferase MenH were known to play an important role in the synthesis of MK-7, there was a lack of in-depth research on their distribution in cells, limiting the further increase in the production of MK-7. We determined the localization of MenA and MenH in cells by fluorescence labeling. Then, the surfactant Triton-100 was used to destroy the cell membrane structure to verify the effect of the integrity of the cell membrane on the synthesis of MK-7. When the concentration of Triton-100 in the fermentation medium was 0.1%, the synthesis of MK-7 was significantly inhibited. When the concentration of Triton-100 reached 0.5%, the synthesis of MK-7 could not be detected. This study reveals that the integrity of cell membrane structure is the prerequisite for the synthesis of MK-7, and MK-7 is synthesized directly on the cell membrane, which is not transported to the cell membrane. The research results provide a direction for in-depth exploration of the synthesis mechanism of menaquinone-7.
CHEN Qi
,
ZHANG Zhihang
,
XIA Hongzhi
,
SUN Yi
,
JIN Ke
,
LYU Xueqin
,
CUI Shixiu
,
LIU Long
. Localization analysis of key proteins during the synthesis of menaquinone-7[J]. Food and Fermentation Industries, 2023
, 49(2)
: 8
-12
.
DOI: 10.13995/j.cnki.11-1802/ts.029324
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