Amino acid sequence of the cold-active alkaline phosphatase from Atlantic cod (Gadus morhua)

The purpose of this study was to analyse the amino acid composition of otolith matrix protein, estimate the proportion of the water-soluble protein fraction, and analyse the effect of matrix composition on otolith visual appearance. Juvenile Atlantic cod (Gadus morhua) were reared under constant temperature and feeding conditions and sampled at the beginning and the end of the experiment. The amino acid composition was dominated by asparagine, glutamic acid, leucine, serine, and proline. A change in amino acid composition was observed with increasing temperature and time, caused by changing proportions of the water-soluble and -insoluble protein fractions. Feeding level had no effect. The relative content of water-soluble protein was linearly related to fish dry weight and temperature. Otolith opacity, defined as the percentage of incident light absorbed by an otolith section, did not differ significantly between experimental treatments. The soluble protein fraction had a positive, albeit insignificant, correlation with opacity. Using opacity and otolith volume, deposited total otolith protein content was estimated with an R2 of 0.91, where otolith volume alone explained 83% of the observed variation.

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Alkaline phosphatase from Atlantic cod (Gadus morhua). Kinetic and structural properties which indicate adaptation to low temperatures

Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology ◽

10.1016/0305-0491(94)00171-p ◽

1995 ◽

Vol 110 (2) ◽

pp. 315-329 ◽

Cited By ~ 32

Author(s):

Bjarni Ásgeirsson ◽

Ralf Hartemink ◽

Jan F. Chlebowski

Keyword(s):

Alkaline Phosphatase ◽

Structural Properties ◽

Low Temperatures ◽

Gadus Morhua ◽

Atlantic Cod

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Nucleotide Polymorphism and Natural Selection at the Pantophysin (Pan I) Locus in the Atlantic Cod, Gadus morhua (L.)

Genetics ◽

10.1093/genetics/157.1.317 ◽

2001 ◽

Vol 157 (1) ◽

pp. 317-330 ◽

Cited By ~ 1

Author(s):

Grant H Pogson

Keyword(s):

Natural Selection ◽

Amino Acid ◽

Gadus Morhua ◽

Atlantic Cod ◽

Amino Acid Level ◽

Amino Acid Substitutions ◽

Significant Heterogeneity ◽

Nucleotide Sequence Variation ◽

Spatially Varying ◽

Spatially Varying Selection

Abstract Molecular studies of nucleotide sequence variation have rarely attempted to test hypotheses related to geographically varying patterns of natural selection. The present study tested the role of spatially varying selection in producing significant linkage disequilibrium and large differences in the frequencies of two common alleles at the pantophysin (Pan I) locus among five populations of the Atlantic cod, Gadus morhua. Nucleotide sequences of 124 Pan I alleles showed strong evidence for an unusual mix of balancing and directional selection but no evidence of stable geographically varying selection. The alleles were highly divergent at both the nucleotide level (differing on average by 19 mutations) and at amino acid level (each having experienced three amino acid substitutions since diverging from a common ancestral allele). All six amino acid substitutions occurred in a 56-residue intravesicular loop (IV1 domain) of the vesicle protein and each involved a radical change. An analysis of molecular variation revealed significant heterogeneity in the frequencies of recently derived mutations segregating within both allelic classes, suggesting that two selective sweeps may be presently occurring among populations. The dynamic nature of the Pan I polymorphism in G. morhua and clear departure from equilibrium conditions invalidate a simple model of spatially varying selection.

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Antifreeze glycoproteins in the plasma of Newfoundland Atlantic cod (Gadus morhua)

Canadian Journal of Zoology ◽

10.1139/z81-296 ◽

1981 ◽

Vol 59 (11) ◽

pp. 2186-2192 ◽

Cited By ~ 34

Author(s):

Choy L. Hew ◽

Don Slaughter ◽

Garth L. Fletcher ◽

Shashikant B. Joshi

Keyword(s):

Amino Acid ◽

High Performance ◽

Gadus Morhua ◽

Atlantic Cod ◽

Antifreeze Proteins ◽

Gel Filtration ◽

Exchange Chromatography ◽

Polar Cod ◽

Antifreeze Glycoproteins ◽

Molecular Weights

The plasma of the Atlantic cod, Gadus morhua, contained antifreeze glycoproteins which were present only during the winter months. The antifreeze proteins were isolated, using gel filtration and ion exchange chromatography, and characterized by high performance liquid chromatography. The antifreeze proteins appeared to consist of at least seven components with molecular weights ranging from 2 500 to 33 000. Chemical analysis of the larger components showed a predominance of alanine, threonine, and galactosamine in a ratio of 2:1:1. The smaller peptides contained proline, in addition to alanine and threonine. The amino acid sequence of the smallest glycopeptide (molecular weight 2500) was found to be Ala Ala Thr Pro Ala Thr Ala Ala Thr Pro Ala Thr Ala Ala.These glycoproteins are very similar, if not identical, in amino acid and carbohydrate composition to those isolated from Antaractic nototheniids and several northern gadoids. The sequence of the smallest glycopeptide from the Atlantic cod is identical to that reported for the polar cod, Boreogadus saida.

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