ENOLASE ACTIVITY AND ISOENZYME DISTRIBUTION IN HUMAN BRAIN-REGIONS AND TUMORS

The distribution of enolase (EC 4.2.1.11) activity and isoenzymes in v arious regions of human brain at different ages (from 23 weeks of gest ation to 95 years) and in brain tumors has been determined. Total enol ase activity increased in all regions with age. No significant differe nces were found in the relative proportions of alpha alpha-, alpha gam ma-, and gamma gamma-enolase isoenzymes in the various brain regions, determined by agarose gel electrophoresis. Type alpha alpha-enolase wa s the predominant isoenzyme, and alpha gamma-enolase represented a sub stantial proportion of the total enolase activity. Astrocytomas, anapl astic astrocytomas, glioblastomas, and meningiomas possessed lower eno lase activity than normal brain. Among astrocytic tumors, total enolas e activity correlated with malignancy. Astrocytomas possessed the lowe st and glioblastomas the highest enolase activity. All tumors possesse d a higher proportion of alpha alpha-enolase and a lower proportion of gamma gamma-enolase than the normal human brain. Among astrocytic tum ors, glioblastomas were the tumors with the highest proportion of alph a alpha-enolase and lowest proportion of gamma gamma-enolase.