ENZYMORPHOLOGIC DEMONSTRATION OF GLUCOSE 6-PHOSPHATE- DEPENDENT GLYCOGEN SYNTHETASE IN MOUSE LIVER’

Mouse liver possesses G-6-P-dependent glycogen synthetase amid not the G-6-P-indepemidenst variety. This fact explains the higher requirement (450mg per 25 ml) for U-6-P in the incuibatiomi mixture for staining mousse liver glycogen synthetase than that presemit imi the Takeuchi amid Glenner substrate mixture. The higher G-6-P conitenst, as well as other conssideratiomss, nieces-sitated the establishment of new conditions for the stainimig reactiomi for glycogeni symsthetase, i.e., pH 9.4, UDPG concentration 200 mg per 25 ml, etc. The presensce of NaF (4.8 X 102M) prevents thermal inactivation of glycogeni synthetase at 37#{176},which is the temperature now recommended for the stainimig reaction. Postfixatiomi amid dehydration makes the sectiomss more readily interpretable and prolongs markedly the life of the iodine staimsim)g reactioms. The new’ procedure is reproducible amid consistent in serial sections of the same animal and among differ-ent animals of like glycogen content. The enzyme appears to be located oms membranes as well as in granules. Some similarities between the characteristics of the depemidemst amid independen