A sample of liver tissue was obtained post-mortem from the body of a patient believed to be genetically deficient in one if the enzymes of the carbohydrate metabolism. A homogenerate of thr liver sample had the following characteristics:
(i) it degraded glycogen to glucose-6-phosphate
(ii) it was unable to make glycogen from any sugar or utilize galactose as an energy source, and
(iii) it synthesised glucose-6-phosphate from lactate.
What enzyme was deficient and why?