A protein activator (GMz-activator) specific for stimulating the hydrolysis of G M ~ ganglioside (GalNAcb1 4GalC3 + 2aNeuAc]/?l-+ 4Glcb1-+ 1’Cer) by &hexosaminidase A has been purified over 1OS-fold with a high yield from human liver. The purification procedure includes the adjustment of the pH of liver extract to pH 4.3, followed by ammonium sulfate precipitation, Sephadex G-200 filtration, an...

We wish to thank Mr G. T. Iles of Belle Vue, Manchester, for supplying us with the sample of python fat used in this investigation, and for the information concerning the animal; also Prof. J. W. Cook, F.R.S., for drawing our attention to the work on bile salts; the University of Glasgow for a scholarship held by one of us (R.P.P.) and Imperial Chemical Industries Ltd., for a grant towards the ...

1. The activity of Ca2+-dependent phosphatidylinositol phosphodiesterase (EC 3.1.4.10) of pig brain against [32P]phosphatidylinositol monolayers at an air/water interface has been measured. As the monolayer pressure was increased a sharp cut-off of enzymic hydrolysis occurred at 33 X 10(-3) N/m. 2. The addition of either phosphatidic acid, phosphatidylglycerol or oleyl alcohol increased the fil...

1. Samples of thyroid and non-thyroid lymph and of thyroid and peripheral venous blood were obtained from primates and cats that had previously been given radioactive iodine. The distribution of the organic radioiodine between the protein and non-protein fractions in these samples was determined. 2. The proportion of the organic radioiodine in the form of iodoprotein was assessed by paper chrom...

Adenosine 5'-(S)-[16O,17O,18O]phosphate was pyrophosphorylated by the combined action of adenylate kinase and pyruvate kinase. The isotopomers of adenosine 5'-[alpha-16O,17O,18O]triphosphate were hydrolysed by venom 5'-nucleotide phosphodiesterase (Crotalus adamanteus) in H2(17)O. Analysis by 31P nuclear magnetic resonance spectroscopy of the resulting adenosine 5'-[16O,17O,18O]phosphate, after...

Alkaline phosphatase of intestinal origin hydrolyzed the S-substituted monoesters of phosphorothioic acid of the type RSP03Na2 (R = -CH2CH2NH2, -CH,CH,NHCOCH,, -CH,COO, or -CH2CHsCOOCzHs) at the S-P bond to yield orthophosphate and the corresponding thioalcohols. The rate of enzymic hydrolysis of cysteamine S-phosphate was measured at pH 9.0 in 0.1 N sodium barbital buffer at different concentr...

It is fairly easy to control the enzymic hydrolysis of proteins in alkaline conditions by measuring the base consumption required to keep the pH constant in the reactor. Unfortunately, however, base consumption is not related in any simple way to the degree of hydrolysis reached at any given moment and to establish this relationship it is essential to find out the mean pK of the alpha-amino gro...