Primary Information
BoMiProt ID	Bomi333
Protein Name	Solute carrier family 29 (Nucleoside transporters), member 1
Organism	Bos taurus
Uniprot ID	Q3ZC83
Milk Fraction	MFGM, Exosome
Ref Sequence ID	NP_001029570.2
Aminoacid Length	456
Molecular Weight	49882
FASTA Sequence	Download
Gene Name	SLC29A1
Gene ID	510932
Protein Existence Status	Unreviewed: Experimental evidence at protein level
Secondary Information
Presence in other biological fluids/tissue/cells	hENT1 protein expression is highest in the adrenal gland, ovary, stomach, duodenum, small intestine, and colon while mRNA was most abundant in the adrenal gland. hENT2 protein expression was highest across a broader range of tissue types including various neurological tissues, segments of the gastrointestinal tract, skin, placenta, parathyroid gland, appendix, testis, urinary bladder, heart muscle, nasopharynx, pancreas, and gallbladder with mRNA being most abundant in skeletal muscle. Protein expression of hENT3 predominates in cerebral cortex, lateral ventricle, ovary, adrenal gland, and testis with higher levels of mRNA expression in placenta, urinary bladder, and ovary
Protein Function	facilitate cross-membrane transport of nucleosides and nucleoside-derived drugs; play an important role in the salvage pathways of nucleotide synthesis, cancer chemotherapy, and treatment for virus infections; polytopic integral membrane proteins that mediate the transport of nucleosides, nucleobases, and therapeutic analogs
Biochemical Properties	As found in humans, competitively inhibited by nitrobenzylmercaptopurine ribonucleoside (NBMPR), nucleosides, deoxynucleosides, and nucleoside-derived anti-cancer and anti-viral drugs; human ENTs consist of 11 transmembrane segments (TMs), a cytoplasmic N-terminus and an extracellular C-terminus, a large extracellular loop between TM1 and TM2, and a large cytoplasmic loop between TM6 and TM7; calculated dissociation constant (Kd) between hENT1 and adenosine is approximately 0.45 ± 0.03 mmol/L; activity of the human ENT3 and ENT4 transporters have been shown to be stimulated at lower pH
Significance in milk	nutrient transport systems for milk precursors and constituents
Site(s) of PTM(s) N-glycosylation, O-glycosylation, Phosphorylation
Bibliography	1. Uhlen, M. et al. (2015) ‘Tissue-based map of the human proteome’, Science, 347(6220), pp. 1260419–1260419. doi: 10.1126/science.1260419. 2. Huang, W. et al. (2017) ‘Functional characterization of human equilibrative nucleoside transporter 1’, Protein & Cell, 8(4), pp. 284–295. doi: 10.1007/s13238-016-0350-x.