Glucose-6-phosphatase (G6Pase), is a multicomponent enzyme system that hydrolyzes glucose-6-phosphate (G6P) in the final step of gluconeogenesis and gluconeolysis. G6Pase localizes to the endoplasmic reticulum, and while liver, kidney, and intestine are the only tissues that express the first identified isoform, G6Pase-α, a second form, designated G6Pase-β, contributes to blood glucose homeostasis in a wider range of tissues. G6Pase-β, also known as SCN4, UGRP or G6PC3 (glucose 6 phosphatase, catalytic, 3), is a 346 amino acid endoplasmic reticulum multi-pass membrane protein that is involved in carbohydrate biosynthesis and the gluconeogenesis pathway. Inhibited by vanadate, G6Pase-β hydrolyzes GP6 to glucose in the endoplasmic reticulum. Due to its necessary involvement in normal glucose metabolism, G6Pase-β may play an integral role in diabetes and glycogen storage diseases (GSDs).