Studies on alkaline phosphatases. 1. Kinetics of plasma phosphatase of normal and rachitic chicks

Motzok, I.

doi:10.1042/bj0720169

Cited by 43 publications

(27 citation statements)

References 14 publications

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“…of the maximum varies with the substrate concentration in the manner described by Rossetal. (1951), Motzok(1959)andMossetal. (1961.…”

Section: Discussionmentioning

confidence: 97%

“…3) gives rise to expressions that describe optimum pH and velocity in terms of the pH-independent constants a and ,B. Since v = l +K./and Vmax- Motzok (1959) interpreted a plot of 1/v0pt. against 1/s as showing two distinct slopes from which he obtained two 'Kin' values.…”

Section: Discussionmentioning

confidence: 98%

“…In Fig. 7(b) we have replotted the data presented in Motzok's (1959) Fig. 7 and included a theoretical curve using constants obtained from the plot of I/ /vvpt.…”

Section: Discussionmentioning

confidence: 99%

“…For instance, Morton (1957) found that Lineweaver-Burk reciprocal plots were nonlinear and his Km values were therefore designated by the substrate concentration at half-optimum velocity. Onthe otherhand, Motzok (1959) recorded linear reciprocal plots but found that Km depended on the enzyme concentration.…”

mentioning

confidence: 97%

“…A second linear relationship, between the reciprocals of substrate (phenyl phosphate) concentration and optimum velocity of hydrolysis with varying pH, was found by Morton (1957). The former relationship has been used (Motzok & Branion, 1959, 1961 Motzok, 1963) as a means of evaluating the effect of dietary and other factors on fowl phosphatases, and the latter has been used to characterize isoenzymes of human tissue phosphatases (Moss, Campbell, Anagnostou- Kakaras & King, 1961).…”

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confidence: 98%

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Kinetic behaviour of calf-intestinal alkaline phosphatase with 4-methylumbelliferyl phosphate

Fernley¹,

Walker²

1965

Biochemical Journal

180

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1. The effects of varying pH, ionic strength and temperature on the parameters K(m) and V(max.) for a purified alkaline phosphatase from calf intestinal mucosa with a new fluorogenic substrate, 4-methylumbelliferyl phosphate monoester disodium salt, and an ammediol-hydrochloric acid buffer system were determined. 2. It was found that, under varying conditions, a relationship exists between K(m) and V(max.) such that V(max.)=beta/(1+alpha/K(m)), where alpha and beta are constants, temperature- and ionic strength-dependent, but pH-independent. It is shown that this relationship accounts satisfactorily for the well-known effect of varying substrate concentration on optimum pH and velocity. 3. The various results are interpreted in terms of a pH-dependent conformational equilibrium between two forms of the enzyme, E(1) and E(2). Only E(1) combines with substrate, and only E(2) reacts to give inorganic phosphate. 4. To account for the pH-variation of K(m) and V(max.) in terms of this theory, it is postulated that the conformational change is associated with a change in pK of two basic groups in the enzyme.

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“…of the maximum varies with the substrate concentration in the manner described by Rossetal. (1951), Motzok(1959)andMossetal. (1961.…”

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 98%

“…In Fig. 7(b) we have replotted the data presented in Motzok's (1959) Fig. 7 and included a theoretical curve using constants obtained from the plot of I/ /vvpt.…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

mentioning

confidence: 98%

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Kinetic behaviour of calf-intestinal alkaline phosphatase with 4-methylumbelliferyl phosphate

Fernley¹,

Walker²

1965

Biochemical Journal

180

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Trout intestinal alkaline phosphatases I. Some physical‐chemical characteristics

Whitmore

Goldberg

1972

J. Exp. Zool.

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Four electrophoretic zones of trout intestinal alkaline phosphatase are described on the basis of charge and molecular weight heterogeneity. Qualitative and quantitative differences in the intestinal phosphatase complement suggest three basic phenotypes, which are exemplified by the isozyme patterns of wild brook trout, hatchery brook trout, and lake trout.The partially purified and separated trout phosphatase zones have been characterized physically and chemically. The data presented clearly place these enzymes in the category of the non-specific alkaline phosphomonoesterases. In common with this group of enzymes, trout phosphatases catalyze the hydrolysis of a wide variety of phosphomonoesters and pyrophosphates, as well as transphosphorylation reactions.

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Nucleotide degrading enzymes in Neurospora crassa

Mattoo

Shah

1974

J of Basic Microbiology

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Considerable amounts of GTP, GMP, adenosine, guanine, and adenine nccnmulated in Neurospom crasaa when a cult'ure grown on low phosphate (0.01%) medium was transferred to a high phosphate (19;) medium. The levels of alkaline phosphatase, nucleotidase, and nucleosidase decreased by 2.4, 5.4, and 3 folds, respectively, in cultures grown on high phosphate medium. Substrate kinetics of these enzymes revealed that: (1) alkaline phosphatase isolated from the organism grown on low phosphate medium demonstrates nonlinear reciprocal plots with two distinct apparent K w values for ,4-glycerophonphate compared to one apparent, K m value (associated with 32% decrease in the apparent VIllar value)

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Studies on alkaline phosphatases. 1. Kinetics of plasma phosphatase of normal and rachitic chicks

Cited by 43 publications

References 14 publications

Kinetic behaviour of calf-intestinal alkaline phosphatase with 4-methylumbelliferyl phosphate

Kinetic behaviour of calf-intestinal alkaline phosphatase with 4-methylumbelliferyl phosphate

Trout intestinal alkaline phosphatases I. Some physical‐chemical characteristics

Nucleotide degrading enzymes in Neurospora crassa

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