Jack L. Strominger

A SPECIFIC MICRODETERMINATION OF GLUCOSAMINE AND THE ANALYSIS OF OTHER HEXOSAMINES IN THE PRESENCE OF GLUCOSAMINE.

Abstract A specific microdetermination of d -glucosamine in the presence of other hexosamines is presented. This method is based on the specificity of yeast hexokinase for d -glucosamine and of yeast acetylating enzyme for d -glucosamine 6-phosphate. When coupled with a method for determination of total hexosamine, the amount of another hexosamine also present (such as galactosamine) can be calculated by difference.

Accumulation of a uridine nucleotide in Staphylococcus aureus as the consequence of lysine deprivation

Abstract Cells of S. aureus , incubated under conditions of lysine deprivation, accumulate a uridine nucleotide, identified as UDPAG-Lact · l -ala · d -glu, a new intermediate in the biosynthesis of the bacterial cell wall. Three means of interfering with cell wall synthesis in S. aureus , each interfering at a different point when viewed in terms of the uridine nucleotides which accumulate, are, therefore, known, viz: lysine deprivation, inhibition by penicillin, and inhibition by gentian violet.

MICRODETERMINATION OF URIDINE DIPHOSPHATE GLUCOSE PYROPHOSPHORYLASE IN BRAIN

While the Occurrence of the UDP-glucose pyrophosphorylase reaction has been noted in brain (MAXWELL, KALCKAR, and BURTON, 1955), optimal conditions for its measurement in that tissue have not been determined previously. The enzyme has been purified from yeast (MUNCH-PETERSEN, 1955), mung beans (GINSBURG. 1958), and rabbit muscle (VILLAR-PALASI and LARNER, 1960~). The present paper describes a new micro-assay and the optimal conditions for measuring UDP-glucose pyrophosphorylase activity in brain. UDP-glucose formed in the pyrophosphorylase reaction (Equation 1 ) is measured by the reduction of diphosphopyridine nucleotide (DPN+) in the presence of UDP-glucose dehydrogenase (Equation 2). UDP-glucose + 2DPN+ UDP-glucuronate + 2DPNH + 2H(2) The assay is both sensitive and convenient and may be especially useful for investigating certain problems mentioned in the discussion.