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K L Smiley

Publications and source records attributed to K L Smiley.

At least 19 recordsLinked to original sources
PubMed1983

Production of 3-hydroxypropionaldehyde from glycerol.

3-Hydroxypropionaldehyde is a precursor to acrolein, which can be used as an intermediate for making acrylic acid and a variety of other useful industrial chemicals. Conversion of glycerol, a renewable resource, to 3-hydroxypropionaldehyde was attempted via action of glycerol dehydrase isolated from Lactobacillus sp. strain NRRL B-1720. This method, however, was unsatisfactory because enzyme activity was lost within 60 to 90 min after the reaction initiation. Fermentation of glycerol by whole cells of Klebsiella pneumoniae NRRL B-199 in the presence of optimal semicarbazide hydrochloride proved more effective. Using this technique, glycerol solutions of 30 g/liter yielded 3-hydroxypropionaldehyde solutions of 13.1 g/liter. Thus, a conversion efficiency equal to 55% of the theoretical maximum was realized.

Journal Article↗
PubMed1976

Exoenzymic activity of alpha-amylase immobilized on a phenol-formaldehyde resin.

Amylose and amylopectin from two starch sources were partially degraded by alpha-amylase immobilized on a phenol-formaldehyde resin. The degradation products were fractioned by gel-permeation chromatography and high-pressure, liquid chromatography. Two distinct fractions were obtained from tapioca amylose. One is a fragment having a molecular weight exceeding 200,000, and the other consists of oligosaccharides of low molecular weight with a degree of polymerization of 1-8. In contrast, treatment of tapioca amylose with soluble alpha-amylase produces a single fraction, nearly all of which has a molecular weight of less than 35,000, with only traces of small oligosaccharides detectable by high-pressure, liquid chromatography. Even wider differences were observed in degradation products from tapioca amylopectin. Similar activity-patterns were obtained with immobilized and soluble enzyme, using corn amylose and corn amylopectin as substrates. Immobilization of alpha-amylase on the resin apparently restricts the activity of the enzyme to the ends of the starch molecules, making it appear to be limited to exoenzymic activity.

Amylases↗
PubMed1976

Alpha-galactosidase production and use in a hollow-fiber reactor.

Soybean milk serves as a base for a variety of beverages designed for consumption in developing countries. Soybean flour contains raffinose and stachyose considered to be responsible for flatulence often associated with these products (J.J. Rackis, D.H. Honig, D.J. Sessa, and F.R. Steggerda, 1970). alpha-Galactosidase, produced on wheat bran, hydrolyzes the galactooligosaccharides of soybean milk.

Aspergillus↗
PubMed1975

Patterns of action of glucoamylase isozymes from Aspergillus species on glycogen.

Glucoamylase isozymes from black Aspergillus species have been freed of all traces of alpha-amylase by chromatography on Bio-Gel P-100, as evidenced by limited hydrolysis of oxidized amylose. Glucoamylase I retains its ability to hydrolyze rabbit-liver glycogen rapidly. By contrast, glucoamylase II hydrolyzes glycogen slowly, and addition of alpha-amylase to glucoamylase II does not enhance its activity toward glycogen. These results indicate that alpha-amylase is not involved in hydrolysis of glycogen by glucoamylase.

Amylases↗
PubMed1975

Properties of D-xylose isomerase from Streptomyces albus.

A partially purified D-xylose isomerase has been isolated from cells of Streptomyces albus NRRL 5778 and some of its properties have been determined. D-Glucose, D-xylose, D-ribose, L-arabinose, and L-rhamnose served as substrates for the enzyme with respective Km values of 86, 93, 350, 153, and 312 mM and Vmax values measuring 1.23, 2.9, 2.63, 0.153, and 0.048 mumol min per mg of protein. The hexose D-allose was also isomerized. The enzyme was strongly activated by 1.0 mM Mg2+ but only partially activated by 1.0 mM Co2+. The respective Km values for Mg2+ and Co2+ were 0.3 and 0.003 mM. Mg2+ and Co2+ appear to have separate binding sites on the isomerase. These cations also protect the enzyme from thermal denaturation and from D-sorbitol inhibition. The optimum temperature for ketose formation was 70 to 80 C at pH values ranging from 7 to 9. D-Sorbitol acts as a competitive inhibitor with a Ki of 5.5 mM against D-glucose, D-xylose, and D-ribose. Induction experiments, Mg2+ activation, and D-sorbitol inhibition indicated that a single enzyme (D-xylose isomerase) was responsible for the isomerization of the pentoses, methyl pentose, and glucose.

Arabinose↗
PubMed1973

Rapid regulation of an anthranilate synthase aggregate by hysteresis.

The anthranilate synthase aggregate from Bacillus subtilis is composed of two nonidentical subunits, denoted E and X, which are readily associated or dissociated. A complex of subunit E and X can utilize glutamine or ammonia as substrates in the formation of anthranilate. Partially purified subunit E is capable of using only ammonia as the amide donor in the anthranilate synthase reaction. The stability of the EX complex is strongly influenced by glutamine and by the concentrations of the subunits. Glutamine stabilizes the aggregate as a molecular species in which the velocity of the glutamine-reactive anthranilate synthase is a linear function of protein concentration. In the absence of glutamine the aggregate is readily dissociated following dilution of the extract; that is, velocity concaves upward as a function of increasing protein concentration. Reassociation of the EX complex is characterized by a velocity lag (or hysteretic response) before steady-state velocity for the glutamine-reactive anthranilate synthase is reached. We propose that association and dissociation of the anthranilate synthase aggregate may be physiologically significant and provide a control mechanism whereby repression or derepression causes disproportionate losses or gains in activity by virtue of protein-protein interactions between subunits E and X.

Ammonia↗
PubMed1971

Free and immobilized glucose isomerase from Streptomyces phaeochromogenes.

Properties were determined of the glucose isomerase from Streptomyces phaeochromogenes NRRL B-3559. The enzyme exhibited a temperature optimum of 80 C and a pH optimum of about 8. The effect of various buffers on activity of the enzyme and the optimum pH were studied. Michaelis constants for glucose and Mg(2+) were 0.25 and 0.025 m, respectively. Co(2+) enhanced enzyme activity. A functional polyacrylamide-entrapped glucose isomerase was prepared. The conditions for entrapment and use of the bound enzyme were examined.

Acrylates↗
PubMed1968

Trnasglucosyl-amylase of Candida tropicalis.

Transglucosyl-amylase was purified 96-fold and partially characterized. The K(m) value with dextrin as substrate was 9.1 mg/ml. Glycerol, an acceptor of d-glucose, appeared to inhibit dextrin hydrolysis noncompetitively. The energy of activation of the enzyme was 7,920 cal/mole. Indirect determinations showed that synthesis of d-glucosyl glycerol was significantly affected by the nature of the amylaceous substrate. Glucosyl-glycerol synthesis did not increase as incubation temperature was raised from 50 to 60 C. Direct determinations by gas-liquid chromatography indicated that the synthesis of glucosyl glycerol, as a function of the concentration of either enzyme, substrate, or glycerol, traced a curvilinear path approaching 15 mg/ml as the maximum. When enzyme, substrate, and glycerol at high concentrations were varied in all possible combinations, however, conditions for producing as much as 47.5 mg/ml of glucosyl glycerol were established.

Candida↗