Table 1.

The activities of key enzymes in glucose-driven energy metabolism with age.

ID	Age	Gender	Activity normalized based on pyruvate kinase				Pyruvte kinase high affinity
			Aldolase	Adenylate kinase	Triose-phosphate isomerase	Hexo-kinase
219	19	f	0.69	0.27	4.87	0.19	20.52
309	21	f	0.12	0.51	4.94	0.04	21.72
308	23	m	0.34	0.59	6.75	0.06	5.81
214	29	m	0.46	0.27	4.90	0.20	7.03
307	44	m	0.48	0.76	7.70	0.11	18.54
302	59	m	1.23	1.74	28.33	0.34	22.43
305	62	f	0.65	1.00	14.48	0.20	11.28
303	69	m	0.81	1.21	11.41	0.17	9.58
221	71	f	0.37	0.57	12.33	0.22	6.23

The enzymatic activities of aldolase, adenylate kinase, triosephosphate isomerase, and hexokinase in 9 human subjects were assessed (age range: 19–71 years). To overcome the significant biological variance, we have normalized the function of each enzyme by pyruvate kinase “high affinity”.