THE HYALURONIDASE OF BRAIN

Abstract— Hyaluronidase (hyaluronate glycanohydrolase, EC 3.2.1.35), with a pH optimum of 3.7, was detected in rat and bovine brain. It degraded hyaluronic acid and, at a slower rate, chondroitin sulphate to a mixture of higher oligosaccharides with N-acetylhexosamine at the reducing end. The enzyme was enriched 5- and 6-fold in a crude lysosomal fraction of rat brain or bovine cerebral cortex, and was further purified to a total enrichment of 9-fold by ammonium sulphate fractionation. The enzyme activity in grey matter was more than twice that found in white matter, and there was no significant change in enzyme activity as a function of increasing age from the neonatal to the adult rat brain. The level of hyaluronidase activity in rat brain is considerably greaterthan that required to account for the rate of catabolism of hyaluronic acid and chondroitin sulphate measured in vivo.     

THE MEASUREMENT OF TRIGLYCERIDE IN BRAIN AND THE METABOLISM OF BRAIN TRIGLYCERIDE IN VITRO

Abstract—

• 1 Triglyceride has been isolated from brain by thin-layer chromatography and determined by absorption of the carbonyl group at 1740 cm^?1. The means of yields from whole mouse brain, whole rat brain, rat brain grey matter, rat brain stem, and incubated slices of rat brain cortex were 0.15–0.17 μmole/g tissue.
• 2 The distribution of fatty esters varied from preparation to preparation. Palmitate, stearate and oleate usually occurred in greatest amounts. Hydrolysis of a preparation of triglyceride from whole rat brain with pancreatic lipase indicated that palmitate was equally distributed between the α and β esters.
• 3 [1-¹⁴C]Acetate was rapidly incorporated into triglyceride of slices of incubated rat brain cortex. When the resulting triglyceride was hydrolysed with pancreatic lipase the distribution of radioactivity amongst the hydrolysis products was consistent with both the α and β esters of the triglyceride having been radioactively labelled.